Category Archives: Quantum Physics
University of Washington team detects atomic ‘breathing’ for … – GeekWire
The UW research team included Adina Ripin (left), lead author of the study and a doctoral student in the physics department, Ruoming Peng (center), co-lead author and a recent UW ECE graduate (Ph.D. 22), and senior author Mo Li (right), a professor in UW ECE and the physics department and the UW ECE associate chair for research.
Most of us dont think of atoms as having their own unique vibrations, but they do. In fact, its a feature so fundamental to natures building blocks that a team of University of Washington researchers recently observed and used this phenomenon in their research study. By studying the light atoms emitted when stimulated by a laser, they were able to detect vibrations sometimes referred to as atomic breathing.
The result is a breakthrough that may one day allow us to build better tools for many kinds of quantum technologies.
Led by Mo Li, a professor of photonics and nano devices in both the UW Department of Electrical and Computer Engineering and the UW Physics Department, the researchers set out to build a better quantum emitter, or QE, one that could be incorporated into optical circuits.
QEs are an essential part of the quantum technology toolkit in that they provide a way to generate individual quantum particles that can be used as qubits. Analogous to bits of information in everyday computing, qubits are used in quantum computing to perform calculations far beyond what can be achieved with classical computers. Typically, a qubit is built from an electron or a photon because of these particles unique quantum properties.
This is a new, atomic-scale platform, using what the scientific community calls optomechanics, in which light and mechanical motions are intrinsically coupled together, said Li. It provides a new type of involved quantum effect that can be utilized to control single photons running through integrated optical circuits for many applications.
To build their QE, the team began with tungsten diselenide, a molecule composed of tungsten and selenium. This was formed into the thinnest of sheets, each only a single atom thick. Two of these sheets were then layered one atop the other and placed over a series of nanopillars, a mere 200 nanometers wide.
This placement on the nanopillars caused the sheets to deform at the point of contact, resulting in a series of regularly spaced quantum dots. Quantum dots are semiconductor particles a few nanometers in size, having unique optical and electronic properties and are a common method of building QEs for quantum applications. Because of the deformation caused by the nanopillars, these are more specifically referred to as strain-induced quantum dots.
By applying a precise pulse of laser light to one of the quantum dots, an electron is knocked away from the tungsten diselenide atoms nucleus. This briefly creates a quasiparticle known as an exciton. This exciton is composed of the negatively charged electron and the corresponding positively charged hole in the opposite sheet. Because they are strongly bound, the electron quickly returns to the atom. When it does this, it releases a single photon encoded with very specific quantum information.
To feasibly have a quantum network, we need to have ways of reliably creating, operating on, storing and transmitting qubits, said Adina Ripin, a lead author of the paper, member of the Mo Li Group, and a doctoral student in the physics department. Photons are a natural choice for transmitting this quantum information because optical fibers enable us to transport photons long distances at high speeds, with low losses of energy or information.
This approach resulted in producing very consistent, high-quality photons that could potentially be used as qubits. By itself, this would make the project a success. However, certain details soon became apparent in the data, meriting a deeper look.
The researchers found that a quasiparticle called a phonon was also being produced in the process of creating each photon. Phonons are an optomechanical phenomenon based on the vibration between atoms and they occur in all matter. Phonons can be thought of as acoustic analogs to photons, with their own quantum waveforms. Though we cant directly see or hear this, Li says the vibrations can be visualized as the breath between atoms.
In this study, the phonons were generated by the vibration between the two atom-thin layers of tungsten diselenide, which acted like tiny drumheads vibrating relative to each other. The UW team found these phonons were tightly correlated to the photon that was being generated.
You can think of phonons in terms of a little spring attached to the layers, Li said. This spring is vibrating, so it directly changes how the electron and the hole can recombine. Because of this, the photon thats emitted changes as well.
Previously, phonons had never been observed in this type of single photon emitter system. Moreover, when analyzing the spectrum of the light emitted, the team found equally spaced peaks representing the phonons different quantum energy levels. Expert analysis by Ting Cao, a quantum theorist and an assistant professor in materials science and engineering, revealed that every single photon emitted by an exciton was coupled with one, two, three or more phonons.
A phonon is the natural quantum vibration of the tungsten diselenide material, and it has the effect of vertically stretching the exciton electron-hole pair sitting in the two layers, Li continued. This has a remarkably strong effect on the optical properties of the photon emitted by the exciton that has never been reported before.
The team was further able to tune the phonon-exciton-photon interaction by applying electrical voltage across the materials. By varying the voltage, they found they could alter the interaction energy of the associated phonons and emitted photons. This was controllable in ways relevant to encoding specific quantum information into a single photon.
I find it fascinating that we were able to observe a new kind of hybrid quantum platform, said Ruoming Peng, also a lead author of the paper, who graduated with his doctoral degree from UW ECE in 2022. By studying the way phonons interact with quantum emitters, we discovered a whole new realm of possibilities for controlling and manipulating quantum states. This could lead to even more exciting discoveries in the future.
Li and his team want to extend their system further, controlling multiple emitters and their associated phonon states. Doing this would allow the quantum emitters to talk to each other, building the basis for new kinds of quantum circuitry. Future applications for these approaches include quantum computing, quantum communications and quantum sensing.
The UW team includes Adina Ripin, Ruoming Peng, Xiaowei Zhang, Srivatsa Chakravarthi, Minhao He, Xiaodong Xu, Kai-Mei Fu, Ting Cao, and Mo Li. The research is supported by the National Science Foundation. Their research paper, Tunable phononic coupling in excitonic quantum emitters was recently published in the journal Nature Nanotechnology.
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University of Washington team detects atomic 'breathing' for ... - GeekWire
Exploring the World of Quantum Metrology: A Comprehensive … – CityLife
Unveiling the Mysteries of Quantum Metrology: A Comprehensive Guide
Quantum metrology, a relatively new and rapidly evolving field, has been garnering significant attention from scientists and researchers worldwide. This burgeoning area of study focuses on the application of quantum mechanics to the science of measurement, offering unprecedented levels of precision and accuracy. As our understanding of the quantum realm deepens, so too does our ability to harness its unique properties for a wide range of practical applications, from atomic clocks to cutting-edge sensors. In this comprehensive introduction, we will explore the fascinating world of quantum metrology, unveiling its mysteries and delving into its potential impact on our lives.
At its core, quantum metrology is built upon the principles of quantum mechanics, a branch of physics that deals with the behavior of matter and energy at the atomic and subatomic scales. Quantum mechanics is notorious for its counterintuitive and often baffling phenomena, such as superposition and entanglement. Superposition refers to the ability of quantum particles to exist in multiple states simultaneously, while entanglement describes the seemingly instantaneous connection between two particles, regardless of the distance separating them. These phenomena, while perplexing, offer a wealth of opportunities for advancing the field of metrology.
One of the most well-known applications of quantum metrology is in the development of atomic clocks, which are widely regarded as the most accurate timekeeping devices in existence. These clocks rely on the vibrations of atoms to measure time, with some models boasting an astonishing level of precision that would not lose a second over the course of millions of years. This remarkable accuracy is made possible by harnessing the principles of quantum mechanics, allowing scientists to fine-tune their measurements to an unprecedented degree.
Beyond atomic clocks, quantum metrology has the potential to revolutionize a wide range of industries through the development of advanced sensors and measurement devices. For example, researchers are currently exploring the use of quantum-enhanced sensors for applications such as gravitational wave detection, magnetic field sensing, and even medical imaging. These sensors leverage the unique properties of quantum particles to achieve levels of sensitivity and precision that are simply unattainable with classical methods.
As the field of quantum metrology continues to grow, so too does our understanding of the underlying principles that govern the quantum realm. One of the most promising areas of research in this regard is the study of quantum entanglement, which has the potential to unlock new levels of measurement precision and accuracy. By exploiting the correlations between entangled particles, scientists can effectively amplify their measurements, reducing the impact of noise and other sources of error. This technique, known as entanglement-enhanced metrology, has the potential to dramatically improve the performance of a wide range of measurement devices, from atomic clocks to advanced sensors.
Despite the tremendous progress that has been made in recent years, the world of quantum metrology remains shrouded in mystery, with many questions still left unanswered. As researchers continue to delve into the quantum realm, it is likely that new and unexpected discoveries will continue to emerge, reshaping our understanding of the universe and its underlying principles. In the meantime, the practical applications of quantum metrology are poised to have a profound impact on our lives, offering unprecedented levels of precision and accuracy in a wide range of fields.
In conclusion, the rapidly evolving field of quantum metrology holds great promise for the future, offering a wealth of opportunities for advancing our understanding of the quantum realm and its practical applications. From atomic clocks to cutting-edge sensors, the unique properties of quantum particles are poised to revolutionize the science of measurement, unlocking new levels of precision and accuracy that were once thought to be unattainable. As we continue to explore the mysteries of quantum metrology, we can look forward to a future where the boundaries of our knowledge are continually pushed, opening up new and exciting possibilities for scientific discovery and technological innovation.
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Exploring the World of Quantum Metrology: A Comprehensive ... - CityLife
Expansion of National Quantum Initiative Pitched to Science … – ww2.aip.org
The House Science Committee heard testimony this month on ideas for expanding the National Quantum Initiative, which is approaching the midpoint of its initial 10-year horizon.
Left to right: National Quantum Coordination Office Director Charles Tahan, former DOE Under Secretary for Science Paul Dabbar, NASA quantum scientist Eleanor Rieffel, Quantum Economic Development Consortium Executive Director Celia Merzbacher, and University of Illinois quantum scientist Emily Edwards testified before the House Science Committee on June 7.
(House Science Committee)
Ideas are percolating for the next phase of the National Quantum Initiative, which Congress enacted five years ago to accelerate development of technologies that leverage quantum information science (QIS). Earlier this month, the House Science Committee held a hearing to solicit views from experts and air lawmakers priorities for a legislative update the committee is drafting.
One possibility discussed was adding more federal agencies to the NQI, particularly NASA, which could follow China in developing quantum communication satellites. Workforce development was identified as another priority, and many Republicans on the committee expressed a strong interest in reinforcing research security measures for quantum technology.
Committee Chair Frank Lucas (R-OK) argued in his opening statement that it is important for the U.S. to stay ahead of China in developing quantum technology, alluding to reports that the Chinese government plans to spend over $15 billion in the area over five years. The global leader in commercial and military quantum applications will have an economic and strategic advantage not seen since the United States ushered in the nuclear age in the 1940s, he asserted.
Quantum physicist Charles Tahan, the director of the National Quantum Coordination Office, presented recommendations at the hearing on behalf of the NQI agencies and noted that complementary proposals had just been issued by the initiatives advisory panel, which he co-chairs.
Tahan highlighted that annual federal funding for QIS R&D has roughly doubled since the start of the NQI, reaching about $900 million in fiscal year 2022. Efforts launched as a result of the initiative include major QIS research centers supported by the Department of Energy and National Science Foundation that are focused on different applications, such as sensing, communications, and computing. The National Institute of Standards and Technology also established a Quantum Economic Development Consortium (QED-C) to help companies coordinate pre-competitive R&D and identify shared supply-chain needs.
The advisory panel proposes that Congress renew the QIS centers authorization for at least another five years, lift the statutory cap on the number of centers, and signal intent to support the initiative beyond its original 10-year time horizon. The panel also notes NIST and NSF did not meet the funding targets the NQI legislation set out for them and it draws attention to additional programs that are authorized but not yet fully funded. In particular, it recommends moving ahead with DOE programs outlined in the CHIPS and Science Act that would be dedicated to developing quantum communication networks and providing researchers access to quantum computing infrastructure.
Tahan offered additional ideas at the hearing for increasing the initiatives focus on transitioning QIS advances into practical applications, such as creating a NIST Center for Quantum Engineering Research and drawing more on NSFs new Directorate for Technology, Innovation, and Partnerships.
He also proposed Congress formally add the State Department to the NQI and create a dedicated international fund to support the quantum partnership agreements the U.S. has struck with partner nations. He further identified NASA, the National Institutes of Health, and the Department of Homeland Security as capable of playing a larger role and welcomed additional coordination with the Department of Defense, which has expanded its work in QIS in parallel with the NQI.
Committee Ranking Member Zoe Lofgren (D-CA) expressed a particular interest in adding NASA to the NQI, soliciting endorsements of the idea from all the witnesses.
One witness, former DOE Under Secretary for Science Paul Dabbar, proposed the committee authorize a joint DOE-NASA program to link satellites to terrestrial quantum networks, stressing that China already launched such a satellite six years ago. He said such an idea had been pitched internally at NASA and that an explicit endorsement from Congress would help it get off the ground. During his time at DOE, Dabbar advocated for building out a quantum internet with national labs as nodes and, after leaving the department, he co-founded the company Bohr Quantum Technology, which focuses on networking applications.
Representing NASA at the hearing was Eleanor Rieffel, director of the Quantum Artificial Intelligence Laboratory at the agencys Ames Research Center in California. She noted that NASA has produced concepts for a space-based quantum networking testbed and is funding development of a quantum gravity gradiometer that would provide 10-times greater resolution than sensors on the GRACE satellites, which precisely measure gravity to detect mass shifts on the Earths surface.
Concerns over research security motivated much of the discussion at the hearing, including Lucas first question to the witness panel. Unfortunately, we know how China is happy to let the U.S. advance fundamental research while it over-invests in the development of leading-edge applications after the fact. In the next five years of the National Quantum Initiative, how can we safeguard our research investments while maintaining our core scientific values? he asked.
Tahan replied that federal agencies have developed protection plans specific to quantum technology and are continuing to refine them, but added that the agencies have also concluded the U.S. benefits from having a relatively open research system.
First and foremost, our goal has to be to continue to move fast, empower our scientists and entrepreneurs, keep the open scientific community. This is a unanimous view from the agencies: we need to keep our open scientific engine of discovery going, he said. He also noted that in 2021 an interagency panel focused on the security implications of quantum technology published a report emphasizing international scholars contributions to the U.S.
Various Republican committee members asked other witnesses to offer perspectives on the matter throughout the hearing.
Dabbar pointed to the technology risk matrix that DOEs national labs developed during his tenure at the department as a model that could be replicated at other agencies. He described the matrix as a list technology-by-technology of whats okay to work with on an open-science basis and what, although it may not be classified (yet), should be restricted on engagement with countries that are adversaries.
QED-C Executive Director Celia Merzbacher added that companies participating in her consortium are in constant dialogue with law enforcement agencies about potential risks. She cautioned against unilaterally applying export controls to quantum technology, saying any such restrictions should be implemented in concert with other countries to avoid disadvantaging U.S. businesses.
Merzbacher emphasized the high level of international activity in the field, observing that the UK, Canada, Australia, Japan, India, and Germany have all recently released or renewed national strategies for quantum technology. She said figures on how much China is spending on quantum science and technology are hard to verify but that the countrys commitment to the field is unmistakable. She estimated that while the U.S. leads the world in quantum computing, China is ahead in quantum communication, quantum sensors, and post-quantum cryptography, citing research by the Australian Strategic Policy Institute.
The hearing also devoted significant attention to workforce development needs in the sector.
Lofgren recounted for instance how she was initially skeptical of introducing students to quantum science at the K12 level but later became convinced it is helpful to expose them early since it is such a counterintuitive subject. She asked Emily Edwards, co-lead of the National Q12 Education Partnership, whether a model curriculum for quantum physics at the pre-college level is under development. Edwards replied that an initial framework has been completed and called for creating at least one national center for quantum education and workforce tasked with fleshing out a model curriculum.
Addressing needs in higher education, Tahan proposed Congress support efforts to equip less research-intensive universities with the infrastructure necessary to educate students in QIS. We need to get quantum computing test beds that students can learn in at a thousand schools, not 20 schools, he said.
He also stressed the relevance of such skills beyond the quantum technology sector. If you think about what it takes to build a quantum computer or a quantum sensor or a quantum network, what are the skills you need? How to design a circuit, how to do microwave and RF engineering, how to do programming those skills, in any industry of the future, are going to be valuable.
Tahan also noted the report from the advisory panel he co-chairs proposes actions to draw more people into the quantum workforce, such as creating new visa pathways for international scholars and new fellowship programs for U.S. citizens and permanent residents pursuing degrees in QIS-related fields.
Training and recruiting talent, both here and across the world, are the most important actions we can take to strengthen U.S. leadership, he argued.
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Expansion of National Quantum Initiative Pitched to Science ... - ww2.aip.org
New Minor Offers Students the Chance to Study the Stars – Manhattan College News
Manhattan Colleges Kakos School of Science will launch a minor in astronomy this fall, giving students the opportunity to explore the universe through a rigorous and challenging curriculum. Astronomy students will be required to take Physics I, Physics II, Astronomy, Topics in Astrophysics and at least one additional elective from the departments varied courses. The Colleges physics department has officially been renamed the Department of Physics and Astronomy.
Students will be dealing with the universe's most captivating physical occurrences, studying everything from planetary atmospheres to the identification and analysis of planets, said Rostislav Konoplich, Ph.D., department chairperson, physics and astronomy and professor of physics. The minor investigates characteristics of galaxies, the stars and black holes within them and the evolution of the universe itself.
Konoplich said that recent discoveries such as observations of gravitational waves from collisions of black holes and detection of high-energy neutrinos, along with the identification of some of their sources, signify a new age of multi-messenger astronomy.
The departments evolution from physics to physics and astronomy is a reflection of increased student and faculty interest in astronomy, according to Bart Horn, Ph.D., assistant professor of physics. This interest could lead to increased enrollment of students in science-related disciplines, according to Konoplich.
Many of our faculty and students do research in the field, including topics such as neutron star astrophysics, multi-messenger astronomy and connections between particle physics and early universe cosmology, Horn said.
Besides the required courses mentioned above, students can choose from a wide variety of electives including Topics in Cosmology, Computational Physics, Mechanics I, Atomic and Nuclear Physics, Quantum Mechanics I, Electromagnetic Waves and Optics.
A newly acquired 130 mm Celestron NexStar reflecting telescope will be used for classes and stargazing events sponsored by the department and the Society of Physics. Horn said the new telescope should be able to view mountains and craters on the moon, planets, stars and deep-sky objects. Farrooh Fattoyev, Ph.D., assistant professor of physics, teaches a section of astronomy with the Arches program and the class has partnered with the Friends of Jerome Park to host public outreach events.
Horn said that everyone in the department is excited about the upcoming solar eclipse that will pass through the western and northern parts of New York on April 8, 2024.
These events happen every few years somewhere on the globe, but only once every few hundred years at any given point on the map, Horn said. The Society of Physics Students has been stocking up on solar filter glasses and if the weather cooperates, were hoping to organize an eclipse-chasing expedition.
"The new Astronomy minor expands options for students at Manhattan College through the department of Physics and Astronomy, " said Marcy Kelly, Ph.D., dean of the Kakos School of Science. The minor will leverage our faculty expertise in astronomy. We are excited to provide our students with opportunities to engage with our faculty in creative and meaningful ways."
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New Minor Offers Students the Chance to Study the Stars - Manhattan College News
Steamboat local who overcame grief looks to share experience with … – Steamboat Pilot & Today
Heidi Petersen was a freshman in high school when she found out her mothers death was due to suicide, not pneumonia, as she had been told the previous decade. A suicide attempt by her brother at the time brought the news to light.
Petersen describes grief as a constant in her life, something that has lived in her, her household and her family members for as long as she could remember.
It affected me in school, Petersen said. I struggled but I just thought I was stupid, as did teachers. I grew up in a house where there was just a lot of sadness that was never really dealt with. I was worried about everybody else around me and did not acknowledge my own grief.
In adulthood, Petersen would lose a good friend who had beaten cancer once but not the second time, and later her father. With time came the recognition of her grief.
She moved to Steamboat in 2013, and for the first time started to work on healing. She spent time in nature and sought professional help. Eventually, she came to the realization it is possible to live with grief in a way thats not debilitating.
After exploring different avenues of coping, Petersen found one that worked, and she realized it could help others as well. Petersen said it was her 51st birthday when she realized that it was now or never, so she set off and created the Path to Healing Grief Retreats. She pulled together resources that helped her cope with her grief, rented a retreat center and set a date for September.
This retreat is bringing together many of the things that were helpful to me in my process of grieving, Petersen said.
The retreat emphasizes using nature to heal and features therapists, body workers, sound healers, herbalists and massage therapists.
Petersen secured the Authentic Living Heartland Retreat Center in Dolores from Sept. 17-23 for her first retreat.
The retreat will include two therapists, Paige Roberts, Ph.D., and Catherine Leitess. Roberts specializes in grief and implements various neuroscience and quantum physics modalities into her practices. Leitess specializes in working with brain injuries, emotional trauma, grief and PTSD.
I started working with Paige and I was amazed at the progress I was making with her in a very short period of time, Petersen said. Her work is very effective and exactly what the retreat needs.
Leitess approached Petersen about wanting to be a part of the retreat. Not wanting to increase the price, Petersen told her she was not sure she could afford to take her on. Leitess wanted to help regardless and volunteered her services without raising the price.
Petersen kept the price to $3,400 for a double room and $3,900 for a single room for the week.
Leitess has training and certifications in Biodynamic Craniosacral Therapy, and she has experience with grief herself. When her husband of 22 years took his life a few years ago, she turned to cranial sacral work. After witnessing the emotional healing that it brought her, she set on a path to share the benefits with others.
Biodynamic Craniosacral Therapy is a form of body therapy generally performed on a massage table that focuses on the inherent health of the body with a focus on the nervous system. The therapist typically looks to bring about natural adjustments from within the bodys own resources.
In addition to counseling, there will be sound therapy and Reiki Energy Healing done. Petersen also will lead hikes and teach yoga, as she is a certified instructor. The retreat has space for eight people and includes a chef and herbalist who will cook for the week. Peterson said much of the food will be plant-based.
Additionally, the Authentic Living Heartland Retreat Center has two labyrinths. These structures created for moving mediation are designed to have people walk in a specific pattern and are meant to be a meditative experience. People can register for the retreat on the Path to Healing Grief Retreats site. Registration closes Aug. 1.
People will have the opportunity to work with Roberts beyond the retreat, and Petersen said she is planning monthly hikes for those who complete the retreat.
Kit Geary is the county, public safety and education reporter. To reach her, call 970-871-4229 or email her at kgeary@SteamboatPilot.com.
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Steamboat local who overcame grief looks to share experience with ... - Steamboat Pilot & Today
No, the laws of physics are not time-symmetric – Big Think
No matter when, where, or what you are in the Universe, you experience time in only one direction: forward. In our everyday experiences, clocks never run backward; scrambled eggs never uncook and unscramble themselves; shattered glass never spontaneously reassembles itself. But if you were to look at the laws of physics that govern the way the Universe works from Newtons laws of motion down to the quantum physics of subatomic particles youd find something peculiar and unexpected: the rules are exactly the same whether time runs forward or backward.
This corresponds to a certain symmetry of nature:T-symmetry, or time-reversal invariance. Our everyday experience indicates to us, quite strongly, that the laws of physics must violate this symmetry, but for decades, we couldnt demonstrate it. From Newtonian physics to Maxwells electromagnetism to the strong nuclear force, every individual interaction ever observed appears to obey this time-reversal symmetry. It was only in 2012 thatwe finally experimentally showed that the laws of physics are differentdepending on which direction time runs. Heres how we figured it out.
A wine glass, when vibrated at the right frequency, will shatter. This is a process that dramatically increases the entropy of the system, and is thermodynamically favorable. The reverse process, of shards of glass reassembling themselves into a whole, uncracked glass, is so unlikely that it never occurs spontaneously in practice. However, if the motion of the individual shards, as they fly apart, were exactly reversed, they would indeed fly back together and, at least for an instant, successfully reassemble the wine glass. Time reversal symmetry is exact in Newtonian physics.
Imagine you and a friend decide to go to Pisa, with one of you standing atop the famous leaning tower and the other located down at the bottom. From the top, whoever throws a ball off the edge can easily predict where it will land down on the bottom. Yet if the person at the bottom were to throw the ball upward with an equal-and-opposite velocity to the ball that just landed, it would arrive exactly at the location where the person at the top threw their ball from.
This is a situation where time-reversal invariance holds: where theT-symmetry is unbroken. Time reversal can be thought of the same way as motion reversal: if the rules are the same whether you run the clock forward or backward, theres trueT-symmetry. But if the rules are different when the clock runs backward from when the clock runs forward, thatT-symmetry must be broken. And there are at least two very good, very fundamental reasons to think that this symmetry cannot hold in all instances.
Changing particles for antiparticles and reflecting them in a mirror simultaneously represents CP symmetry. If the anti-mirror decays are different from the normal decays, CP is violated. Time reversal symmetry, known as T, must be violated if CP is violated. The combined symmetries of C, P, and T, all together, must be conserved under our present laws of physics, with implications for the types of interactions that are and arent allowed.
The first is a proven theorem in physics known astheCPTtheorem. If you have a quantum field theory that obeys the rules of relativity i.e., is Lorentz invariant that theory must exhibitCPT-symmetry. What we call C, P, and T symmetries are three symmetries that are both discrete and fundamental in the context of the Standard Model of particle physics:
TheCPTtheorem tells us that the combination of all three symmetries, C and P and T all together, must always be preserved. In other words, a spinning particle moving forward in time must obey the same rules as its antiparticle spinning in the opposite direction moving backward in time. IfC-symmetry is violated, thenPT-symmetry must also be violated by an equal amount to keep the combination of CPT conserved. Since the violation of CP-symmetry had already been demonstrated long ago (dating back to 1964), we knew thatT-symmetry had to be violated as well.
If you create new particles (such as the X and Y here) with antiparticle counterparts, they must conserve CPT, but not necessarily C, P, T, or CP by themselves. If CP is violated, the decay pathways or the percentage of particles decaying one way versus another can be different for particles compared to antiparticles, resulting in a net production of matter over antimatter if the conditions are right.
The second reason is that we live in a Universe where theres more matter than antimatter, but the known laws of physics are completely symmetric between matter and antimatter.
Its true that there must necessarily be additional physics to what weve observed to explain this asymmetry, but there are significant restrictions on the types of new physics that can cause it. They wereelucidated by Andrei Sakharov in 1967, who noted:
Even if we hadnt observedCP-violating interactions directly, wed still have known that they must occur in order to create a Universe thats consistent with what we observe: a Universe that isnt matter-antimatter symmetric. And therefore, since T-violation is necessarily implied if you have the required CP-violation (in order to conserve the combination of CPT), time-reversal symmetry, orT-symmetry, cannot hold true under all circumstances.
In the Standard Model, the neutrons electric dipole moment is predicted to be a factor of ten billion larger than our observational limits show. The only explanation is that somehow, something beyond the Standard Model is protecting this CP symmetry in the strong interactions. If the C symmetry is violated, so is PT; if P is violated, so is CT; if T is violated, so is CP.
But theres an enormous difference, in any science, between either theoretical or indirect evidence for a phenomenon and a direct observation or measurement of the desired effect. Even in instances where you know what the outcome must be, experimental verification must be demanded, or we run the risk of fooling ourselves.
This is true in any area of physics. Sure, we knew by watching the timing of binary pulsars that their orbits were decaying, but only with the direct detection of gravitational waves could we be certain thats how the energy was being carried away. We knew that event horizons must exist around black holes, but only by directly imaging them did we confirm this prediction of theoretical physics. And we knew that the Higgs boson must exist to make the Standard Model consistent, but only by discovering its unambiguous signatures at the LHC were we able to confirm it.
So that set up the key task for physicists: rather than measuring other types of violations (like C, P, or CP) and using those violations in combination with what must be conserved (CPT) to conclude that the conjugate symmetry (e.g., PT, CT, and T, respectively) must also be violated, wed need to explicitly and directly find a way to put T-symmetry to the test in an instance where it should be violated.
The first robust, 5-sigma detection of the Higgs boson was announced a few years ago by both the CMS and ATLAS collaborations. But the Higgs boson doesnt make a single spike in the data, but rather a spread-out bump, due to its inherent uncertainty in mass. Its mass of 125 GeV/c is a puzzle for theoretical physics, but experimentalists need not worry: it exists, we can create it, and now we can measure and study its properties as well. Direct detection was absolutely necessary in order for us to be able to definitively say that.
This would require a lot of thought, and a very clever experimental setup. What one must do is design an experiment where the laws of physics could be directly tested for differences between an experiment that runs forward in time versus one that runs backward. And since in the real world time only runs forward, this requires some truly creative thinking.
The way to think about this is to remember how entangled quantum states work. If you have two quantum particles that are entangled with one another, you know something about their combined properties, but their individual properties are indeterminate until you make a measurement. Measuring the quantum state of one particle will give you some information about the other one, and will give it to you instantaneously, but you cannot know anything about either individual particle until that critical measurement takes place.
Typically, when we think about quantum entanglement of two particles, we perform experiments involving stable particles, like photons or electrons. But theres only one type of physics process whereCP-violation is known to occur: through decays that proceed through the weak nuclear interaction.
When the neutral kaon decays, it typically results in the production of either two or three pions. Supercomputer simulations are required to understand whether the level of CP-violation, first observed in these decays, agrees or disagrees with the Standard Models predictions.
In fact, this direct type ofCP-violationwas observed in 1999, and by theCPTtheorem,T-violation must occur. Therefore, if we want to test for direct violation of time reversal symmetry, wed have to create particles whereT-violation occurs, which means creating either baryons or mesons (unstable composite particles) that decay via the weak interactions. These two properties, of quantum indeterminism and of unstable particles that decay through the weak interactions, were what we needed to leverage in order to design the exact type of experiment required to test for the direct violation ofT-symmetry.
The way to go about testing time reversal violation directly was first proposedonly quite recently, as the technology to produce large numbers of particles that contain bottom (b) quarks has only come about in the past few years. The particle(the Greek letter upsilon) is the classic example of a particle containing bottom quarks, as its actually a meson made of a bottom quark and a bottom antiquark pair.
Like most composite particles, there are many different energy states and configurations it can exist in, similar to how the hydrogen atom exhibits a variety of possible energy states for the electron to be in. In particular, it was suggested that the 4s energy state the third excited spherically symmetric energy level holds some special properties, and might be the best candidate for observingT-symmetry violation directly.
In an atomic system, each s orbital (red), each of the p orbitals (yellow), the d orbitals (blue) and the f orbitals (green) can contain only two electrons apiece: one spin up and one spin down in each one. In a nuclear system, even in a meson which has just a quark and antiquark, similar orbitals (and energy states) exist. In particular, the 4s state of the Upsilon () particle has particularly interesting properties, and was created hundreds of millions of times for the BaBar collaboration at SLAC.
Why would this be the case?
Because the(4s) particle, when you create one, decays into into both a neutral B-meson (with a down quark and an anti-bottom quark) and a neutral anti-B-meson (with a bottom quark and an anti-down quark) about 48% of the time. At an electron-positron collider, you have the freedom to tune your collisions to occur at the exact energy needed to create a (4s) particle, meaning that you can create enormous numbers of B-mesons and anti-B-mesons for all your particle physics needs.
Each of these mesons, either a B-meson or an anti-B-meson, can decay in a few possible ways. Either you can produce:
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This is interesting, because the first decay has a known value for its CP, the second has a known value for its CP thats opposite to the first, and the third decay identifies whether its a B-meson or anti-B-meson by virtue of the sign of the charge on the lepton. (A positively-charged anti-lepton indicates a B-meson decay; a negatively-charged lepton indicates an anti-B-meson decay.)
A setup of the system used by the BaBar collaboration to probe time-reversal symmetry violation directly. The (4s) particle was created, it decays into two mesons (which can be a B/anti-B combination), and then both of those B and anti-B mesons will decay. If the laws of physics are not time-reversal invariant, the different decays in a specific order will exhibit different properties. This was confirmed in 2012.
Knowing that information lets us set up a method for detecting T-symmetry violation. Whenever one member of the B/anti-B pair of mesons decays into a J/ and a Kaon while the other member decays into a lepton (plus other particles), this gives us the opportunity to test for time-reversal violation. Because these two particles, the B-meson and the anti-B-meson, are both unstable, their decay times are only known in terms of their half-lives: decays dont occur all at once, but at random times with a known probability.
Then, youll want to make the following measurements:
This is a direct test of time-reversal violation. If the two event rates are unequal, theT-symmetry is broken. After the creation of over 400 million (4s) particles, time-reversal violation was detected directly: a feat accomplished by the BaBar collaboration back in 2012.
There are four independent time-reversal-violating asymmetries in the decaying (4s) system, corresponding to decays into charged leptons and charm quark-antiquark combinations. The dashed blue curve represents the best fit to the BaBar data without T-violation; you can see how absurdly bad it is. The red curve represents the best-fit data with T-violation. Based on this experiment, direct T-violation is supported at the 14-sigma level.
The test for whether you can reverse the initial and final entangled states in the 4s-excited state of the -meson is, to date, the only test ever performed to see ifT-symmetry is conserved or violated in a direct fashion. Just as anticipated, the weak interactions really do violate thisT-symmetry, proving that the laws of physics are not perfectly identical dependent on whether time is running forward or backward.
In particle physics, the gold standard for experimental significance is a threshold of 5-sigma. Yet BaBar physicists achieved a statistical significance of this result at a 14-sigma level: a remarkable accomplishment.
So why, then, is this groundbreaking result something youve likely never heard about before?
Because at right around the same time, in the same year, in the world of particle physics, the results of the BaBar collaboration were overshadowed by slightly bigger particle physics news occurring at nearly the same time: the discovery of the Higgs boson at the Large Hadron Collider. But this result, demonstrating that the laws of physics are not time-symmetric, might be Nobel-worthy as well. The laws of nature are not the same forward and backward in time. Eleven years after it was established, its time the world truly knew about the magnitude of this discovery.
Read more:
New method to find Majorana particles tested for the first time – Phys.org
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Fifteen years ago, an alternative technique to look for the elusive Majorana particles was conceived theoretically. But no one carried out the experiment, until now. Physicist Jianfeng Ge and his colleagues from the Allan lab of the Leiden Institute of Physics have now successfully carried out the first measurements. The work is published in the journal Nature Communications.
There are a few ways in which physicists can look for Majorana quasiparticles. The main approach is based on conductivity measurements, but that hasn't provided the definitive results scientists hoped for. Therefore, Ge looked for a new approach. "Back when I was at Harvard, I talked to my colleague Eugene Demler about shot noise measurements that should be able to identify Majoranas. He had theorized this fifteen years ago, but no one ever tried it. I thought it was promising so I convinced Milan Allan from the Quantum Matter group to do it. And now we have our first results."
Majoranas are hypothetical particles that are their own antiparticles. This makes them different from any of the particles we already know, and finding them could lead to new discoveries in physics. Ge is actually looking for Majorana quasiparticles in quantum matter. This is a collection of electrons that behave similarly to a Majorana particle.
One of the reasons scientists want to find Majoranas is their potential to revolutionize quantum computing. The qubits that are currently used in quantum computers are not very stable and prone to errors. Majorana qubits could be the long-sought cornerstone for fault-tolerant quantum computers.
The Majorana particles are expected to live in the vortices of an iron-based superconductor that Ge studies. "These vortices are only a few nanometers in size. Only in recent years technology has advanced to the point where we can measure at this small scale," he explains. "We are the first ones in the world to do this experiment. I find that very exciting."
The results are very promising at this stage. "We nailed down the origin of the quasiparticles within two possible explanations, one of which is Majoranas. These measurements pave the way for ultimate proof of Majoranas. We learned a lot and know how to improve the setup for future measurements."
"I share the enthusiasm about the potential for quantum computing but it is not what excites me most about this research," Ge says. "What drives me is curiosity. I want to understand the fundamental principles of the physics itself. It will be a long journey to find the ultimate proof for Majorana particles, let alone develop applications like a quantum computer. But with this experiment we know what to do next. It will not be easy and take a lot of technical instrument development, but I am proud that we are one step closer to finding Majoranas."
More information: Jian-Feng Ge et al, Single-electron charge transfer into putative Majorana and trivial modes in individual vortices, Nature Communications (2023). DOI: 10.1038/s41467-023-39109-w
Journal information: Nature Communications
Originally posted here:
New method to find Majorana particles tested for the first time - Phys.org
Quantum Metrology: The Science of Measuring the Immeasurable – CityLife
Quantum Metrology: The Science of Measuring the Immeasurable
Quantum metrology, a rapidly growing field of research, is pushing the boundaries of measurement precision and accuracy by harnessing the unique properties of quantum mechanics. This cutting-edge discipline aims to develop new measurement techniques and instruments that can detect and quantify the tiniest of changes in physical quantities, such as time, distance, and temperature, with unprecedented sensitivity and resolution. As a result, quantum metrology has the potential to revolutionize various industries, from telecommunications and computing to healthcare and environmental monitoring.
At the heart of quantum metrology lies the concept of quantum entanglement, a phenomenon in which two or more particles become correlated in such a way that the state of one particle cannot be described independently of the state of the other particles, even when they are separated by vast distances. This counterintuitive property of quantum mechanics allows researchers to exploit the correlations between entangled particles to improve the precision of measurements beyond the limits imposed by classical physics.
One of the most promising applications of quantum metrology is in the field of atomic clocks, which are the most accurate timekeeping devices in existence. These clocks rely on the vibrations of atoms to measure time with incredible precision, and they play a crucial role in various technologies, such as global positioning systems (GPS), telecommunications, and financial transactions. By harnessing the power of quantum entanglement, scientists have been able to develop atomic clocks that are even more accurate and stable than their classical counterparts, paving the way for a new generation of timekeeping devices with unparalleled performance.
Another area where quantum metrology is making significant strides is in the realm of gravitational wave detection. Gravitational waves, ripples in the fabric of spacetime caused by the acceleration of massive objects, were first detected in 2015 by the Laser Interferometer Gravitational-Wave Observatory (LIGO). This groundbreaking discovery opened up a new window into the universe, allowing scientists to observe celestial events that were previously hidden from view. However, the detection of gravitational waves is an incredibly challenging task, as these signals are extremely weak and can be easily drowned out by background noise. Quantum metrology offers a solution to this problem by enabling the development of more sensitive detectors that can pick up even the faintest of gravitational wave signals, thus providing valuable insights into the mysteries of the cosmos.
In addition to these high-profile applications, quantum metrology has the potential to transform a wide range of other fields. For instance, researchers are exploring the use of quantum techniques to improve the sensitivity of magnetic resonance imaging (MRI) scanners, which could lead to earlier detection of diseases and more accurate diagnoses. Moreover, quantum-enhanced sensors could be employed in environmental monitoring to detect minute changes in temperature, humidity, and air quality, thereby enabling more effective responses to climate change and pollution.
Despite the tremendous promise of quantum metrology, there are still numerous challenges that need to be overcome before its full potential can be realized. One of the main obstacles is the susceptibility of quantum systems to decoherence, a process in which the fragile quantum states of particles are disrupted by their interactions with the environment. This issue can lead to a loss of entanglement and a reduction in measurement precision, thus limiting the practical applications of quantum metrology. Researchers are actively working on developing new techniques and materials to mitigate the effects of decoherence and enhance the robustness of quantum systems.
In conclusion, quantum metrology represents a bold new frontier in the science of measurement, offering the tantalizing prospect of measuring the immeasurable with unprecedented accuracy and precision. As researchers continue to push the limits of this emerging field, we can expect to see a plethora of groundbreaking innovations that will reshape our understanding of the world and unlock new possibilities in technology and science.
Continued here:
Quantum Metrology: The Science of Measuring the Immeasurable - CityLife
16-year-old graduate plans for college and INL internship – East Idaho News
AMMON - Brecken Allegood is 16-years-old and was technically a junior at Hillcrest High School, but was able to graduate this year.
He says hes able to graduate early because he had the resources available that have allowed him to do it.
I did my eighth grade year and the first half of my ninth grade year at White Pine STEM Academy. It is a very small school, so it was tailored to the people who are driven and want to do a bunch of things, Brecken explained. So I was able to take a bunch of high school there in eighth grade, so I got almost half a year of high school done in eighth grade.
He checked his graduation requirements and realized he could graduate early with no sweat, so he decided to pursue it.
A lot of it comes from self motivation. I push myself really hard to do the best that I can and I always give 110 to everything, Brecken said.
While at school, he has been a part of National Honor Society and has taken AP classes. His teachers say he is a math wiz for competitions. Hes competed in the U.S. Department of Energy National Science Bowl Competition in Washington DC. Its a nationwide academic competition that tests students knowledge in all areas of science and mathematics.
Hes played club soccer and swam on the Hillcrest High School team last year.
Brecken is originally from Fairbanks, Alaska and loves the winter season.
Winter is by far my favorite season and I am a big skier. Both cross-country and alpine, he said.
He is also musically talented and is a violinist. He has been playing for 12 years ever since he was four years old.
I played with the orchestra for all of my years here at Hillcrest. Last year, I was a soloist for the final concert and this year I am the soloist for the final concert. Schindlers List is the final piece. Its a ton of fun. I enjoy it, he said.
After high school, Brecken plans to go to college. He is on the waitlists for Johns Hopkins and Tufts University. He said if he doesnt get into either of those, hes got a nearly-full-ride scholarship to Michigan Tech.
For college, I am planning to pursue either nuclear engineering or quantum physics. Both of those fields and particle physics in general, are just very interesting to me, he said. After that, in the long term, I am trying to decide if I want to pursue the engineering track or more of the pure science track.
He had an internship at Idaho National Laboratory last summer and is doing it again this summer. He said INL would be a great place to work in the future.
I could come back there and work on small modular reactor projects or other things like that. I think I have the resources and ability to really help the planet with our energy problem and our climate crisis and I want to do that to the best of my ability, Brecken said.
See the article here:
16-year-old graduate plans for college and INL internship - East Idaho News
Confuting Hawking: He lives! | Nation – Nation
Stephen Hawking is not a genius because he can do complex math; it is because he can explain complex math to a simple, stupid brain like mine. I reviewed A Brief History of Time and profiled him for the Sunday Nation many years ago.
I am just getting around to reading Brief Answers to the Big Questions, which, as you must know, was published in 2018. I was too busy with the so-called malaya business to read one of the most delightfuland important booksto come out of humanity. Imagine!
Some of the questions Prof tries to answer are the obvious: Is there God? What is the origin of the universe? Is there intelligent life in the universe? God knows we are fumbling with these questions; perhaps we spend so much time inventing weapons and oppressing each other.
I came across the most amazing theory from one of those accounts I follow on Teura (perhaps Twitter for you; thats what we Amerucans call it in Makandune). These folks theorised that our universe might exist inside a Black Hole. In classical physics, Black Holes, created by super-massive stars when they run out of juice and collapse upon themselves, are regions of Space that are so dense, with gravity so strong that nothing, not even light, can escape.
The assumption in old physics is that nothing exists beyond the Event Horizonthe point of no return, where even time itself comes to a halt. At the centre of the Black Hole is a singularity; a point of infinite density and zero volume where even the laws of Nature break down. So, how can our universe exist in that mess?
In comes the new physics. According to quantum physics, some information and, possibly, structures survive beyond the Event Horizon. And the singularity may not be a point, after all; it could be a sphere or torus; if that be the case, then the singularity could form a wormhole, creating a shortcut in space-time (like matter and energy, space and time have their own dalliance and the thought of explaining it makes me ill) and, therefore, linking two distant regions. So, in the thinking here, there could be a highway out of a Black Hole.
The other possibility is that the singularity is not a point at all; neither is it a sphere or torus: It could be a hypersphere or hyper-torus. This would create a bubble universe, a self-contained region of space-time that has its own laws of physics and constants. In this case, the bubble universe exists inside a Black Hole and our observable universe could be a portion of it. (Our Universe Exists Inside of a Black Hole of Higher Dimensional Universe Physics-Astronomy.Dotcom). Please read the article for yourself and forgive me for reproducing large chunks; it happens when concepts are only half-understood.
Now lets turn to Prof Hawkings arguments against the existence of God. His arguments, as always, are neither flippant nor made out of spiritual depravity. He is a thorough-going scientist who believes that, as a scientist, scientific determinism is a basic principle of the universe: That the laws of nature explain everything, that these laws are unchangeable and universal. They apply not just to the flight of a ball but to the motion of a planet and everything in the universe. Since these laws govern everything, apply to everything, and are unchangeable and unbreakable, in these circumstances, I think Prof is struggling with Gods JD.
What about the creation of the universe? Hawking believes the universe was created spontaneously from nothing and is actually nothing. Well, it consists of matter, energy and space; but we already know from Einstein (E=MC2) that matter and energy are more or less the same thing. The positive energy that exists in the universe is matched by an exact amount of negative energy. Two always cancel out, meaning the universe is really nothing.
He relies on quantum physics and the laws of quantum mechanics, which allow small particles, such as protons, to spontaneously appear randomly and disappear equally randomly. His argument is that the original particle need not have been created; it could have been a random event.
Now here is where we get the bugger. He argues that if you go back in time you arrive at a very very small, very dense point; in other words, a Black Hole. Then he establishes the decay of time in a Black Hole: A clock being sucked into a Black Hole shows time slowing down as it approaches the thing and stops altogether at the Event Horizon.
Therefore, since the Big Bang originated in a Black Hole, there was no time before the Big Bang. And there was no cause for the Big Bang because there was no time for the cause to exist in. So there couldnt be a creator because there would be no time for them to exist in.
However, quantum physics now accepts that Black Holes are far from the end of information and structure. As a matter of fact, they could be the home of wormholes and universes. And, therefore, He lives!
Is there an insurgence taking root in northern Kenya? Isnt it time for Prof Kindiki and his brother Duale in Defence to swing into action before it is too late?
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