Category Archives: Quantum Physics
Young Australians share how they built careers in the middle of COVID pandemic – ABC News
Seiji Armstrong is on a mission to make the internet safer a task that's never been more daunting than during the pandemic.
"Whenever there's a global event, abusers out there become opportunistic, and they'll take advantage of information channels and propagate misinformation," he said.
"We have to be able to detect a lot of different types of abuse that might happen on the internet."
That's fuelled his work with Google, developing machine-learning algorithms to pick up on online abuse or content that violates policies.
Mr Armstrong is one of the recipients of the 2021 40 under 40 Most Influential Asian-Australians Awards, an initiative of the Asian-Australian Leadership Summit. The ABC is a media partner.
He's half-Japanese and half-Australian he was born in Australia but moved to Japan when he was three, learning Japanese as his first language.
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When he came back to Australia at age eight, he couldn't speak English at first, and he was bullied at primary school.
"There was always a feeling of not quite fitting in where I was," he said.
"There's always low-key racism and a reminder that, 'Yeah, you're cool, but you're not quite 100 per cent Australian'."
Physics, he said, became an obsession and a way for him to "show the world that I belonged".
"I always had to prove myself to people. Or at least I felt like I did," he said.
He once would have described making the switch from quantum physics to being a cyber security expert as a "happy coincidence".
"But the more I think about it, my upbringing and things that I experienced kind of motivated me to be in a place where I could do something meaningful," he told the ABC.
"You turn on the news and the world is burning down. What am I doing in a lab, in the dark, playing with laser beams, trying to make a quantum computer?"
With lockdowns pushing more people online and using the internet in new ways, he said there's a need to develop new protections quickly.
He's finding solutions to some of the problems exacerbated by the pandemic, just like some other Asian-Australian Leadership award winners, who are carving outspace to thrive online.
Diana Nguyen struck comedy gold in the unlikeliest of places LinkedIn.
When live festivals and stand-up were cancelled at the start of the pandemic, the Melbourne actor and comedian had to re-think how she would perform.
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She launched Snortcast a podcast where she interviews fellow comedians about their craft.
"I really attacked the internet to bring joy to people," she said.
Making Australia's Vietnamese community more visible and celebrating her heritage has been an ongoing project for Nguyen.
That includes finding new audiences in the US and Vietnam for her 2019 web series Phi and Me the first Australian-Vietnamese family comedy show on LinkedIn and TikTok.
The heart of the story about first-generation Australian kids whose parents have risked so much and fled the trauma of war not only resonated, but could also be funny, she found.
"We wanted to celebrate the humour in it, we didn't want to just show all struggle, but we wanted to show the lovely, beautiful love story between a mother and her daughter," she said.
For a comedian who thrived on live performances, "success" also had to be redefined.
"To be honest, it was a lot of self-healing. I'm usually an extrovert, but I really learned how to be an introvert during lockdown last year," she said.
"My life depended on 'live' I'm a live theatre performer.
"And so that was a really interesting period for me, that I needed a pandemic to stop the machine of doing [constant] shows."
For entrepreneur Jeanette Kar Yee Cheah, CEO and founder of education technology company Hacker Exchange (HEX), it's all about looking at the future of work.
She said creativity is essential during a time of pandemic as well as the ability to quickly adapt to new technology adding that disruption could give birth to innovation.
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"What I'm seeing in people who continue to be successful is the ability to rapidly assess the situation and do scenario planning and pivot," she said.
"The barriers to entry to starting a tech company have never been lower. You don't need to know how to code, you don't need to know how to write a business plan in order to become a great tech entrepreneur right now.
"So it's really a great opportunity for anyone who wants tostep up and try something."
She said based on her own upbringing, Asian Australians were often taught to be high achievers but that shouldn't stop people from having a go.
"We're coached and socialised into being perfectionists quite often," she said.
"And that's definitely a mindset I had to lose as an entrepreneur because perfection is never something you achieve the first time around."
Sabra Lane brings you a fortnightly collection of stories that aim to inspire, engage and create hope.
The pandemic hasn't stopped her from running an online global challenge on how to protect human rights in a "post-truth world", or organising anintensive hackathon, where participants are encouraged to find ways to increase happiness for a segment of the community.
HEX's next focus is aprogram designed to be a kind of professional gap year.
Ms Cheah said she saw a need for it, with the traditional overseas gap year off the cards due to travel restrictions, and young people not wanting to spendseveral thousand dollars on a course when they did not know what they wanted to do in the current environment.
"At a time when people are fearful, and when things are changing so fast, it's absolutely the time to create new businesses, new solutions," she said.
"There's a certain part of people's psyche right now where they're open to new things."
Stanley Wang became a principal in mid-2020 at Melbourne's Abbotsford Primary School,the home to the oldest Chinese-English bilingual program.
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A back-of-the-envelope estimate from experts suggests only around 130 Australians without Chinese heritage can speak Mandarin.
That's something Mr Wang is hoping to change both through his school, and in an online conversation club he started earlier this year.
"Learning any language has the cognitive benefits, the intercultural understanding," he said, adding it can help students challenge assumptions and broaden their perspectives.
Travel for his students to their sister city in China has been put on hold due to the pandemic, but they've learned to make the most of it.
"We have actually leveraged the opportunity to do a lot more small-scale but frequent dosages of online interaction between students from our school and other Chinese-speaking regions," he said.
"That has been very powerful for the students because they are not just preparing for that one-off burst of excitement, but actually seeing that this is about relationship building, too."
With COVID-19 lockdownsdragging on, some parents are feeling anxious about the impact of remote learning on their children's education.
For students who feel like the pandemic has thwarted their ambitions or hit pause on their learning, he has some advice.
"I look at it almost like building your own capacity to function in another country or another culture," he said.
"Despite the fact that this experience may not be ideal, and it requires a lot of resilience, I think it will pay off in the long run," he said.
Seiji Armstrong, Diana Nguyen,Jeanette Kar Yee Cheahand Stanley Wang are 2021 recipients of the 40 under 40 Most Influential Asian-Australians Awards, an initiative of theAsian-Australian Leadership Summit.
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Young Australians share how they built careers in the middle of COVID pandemic - ABC News
Top physics prizes awarded to UNSW researchers – UNSW Newsroom
Two UNSW Sydney researchers have been awarded prestigious medals by the Australian Institute of Physics (AIP). The medals recognise outstanding achievements in physics at various career stages.
Scientia Professor Andrea Morello, UNSW Engineering won the 2019 Walter Boas Medal for Excellence in Research, the senior award for research excellence in physics in the country.
The AIP said Prof. Morello received the award for his world-first demonstration of quantum information processing with single spins in silicon, and for developing the fundamental components of a silicon-based quantum computer.
I am truly honoured by the award of the Walter Boas Medal, Prof. Morello said.
In this case, the award recognises the world-leading work of a team of outstanding students, researchers and academic colleagues who have worked with me in the last decade and have kick-started the use of silicon technologies for the second quantum revolution.
Scientia Professor Andrea Morello. Image: UNSW Engineering.
Dr Samuel Gorman, UNSW Science won the 2019 Bragg Gold Medal for Excellence in Physics. The Bragg Gold Medal recognises the PhD student who is judged to have completed the most outstanding PhD thesis in physics at an Australian university in the past year.
Each university is only allowed a single nominee each year and Dr Gorman won for his thesis titled "Charge and spin dynamics in multi-donor systems".
"Receiving the Bragg Medal is amazing recognition for many years of work on a very interesting subject, Dr Gorman said. I am extremely grateful to the AIP for selecting me and I would like to thank everyone who has helped me during my PhD. This award is the perfect ending to a fantastic PhD experience."
Dr Samuel Gorman. Image: UNSW.
UNSW Deputy Vice-Chancellor Research and Enterprise Professor Nicholas Fisk congratulated the recipients.
The Walter Boas Medal is a wonderful recognition of the work and impact of Prof. Morello as a true leader in the field of quantum computing. We are equally proud of Dr Gormans outstanding contribution to this frontier technology research which has been rightly recognised with the Bragg Gold Medal, Prof. Fisk said.
The AIP announced the 2019 and 2020 awards together this year. The Walter Boas Medal was established by the AIP in 1984 to promote excellence in research in physics and to perpetuate the name of Walter Boas an eminent scientist and metallurgist who worked on the physics of metals.
The Bragg Medal was instituted by the AIP to commemorate Sir Lawrence Bragg and his father Sir William Bragg. The pair received the Nobel Prize for Physics in 1915 for their analysis of crystal structures using X-rays.
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Top physics prizes awarded to UNSW researchers - UNSW Newsroom
Our Universe may have a fifth dimension that would change everything we know about physics – BBC Science Focus Magazine
In 1905, Albert Einstein showed in his Special Theory of Relativity that space is intimately connected to time via the cosmic speed limit of light and so, strictly speaking, we live in a Universe with four dimensions of space-time. For everyday purposes however, we think of the Universe in three dimensions of space (north-south, east-west, up-down) and one dimension of time (past-future). In that case, a fifth dimension would be an extra dimension of space.
Such a dimension was proposed independently by physicists Oskar Klein and Theodor Kaluza in the 1920s. They were inspired by Einsteins theory of gravity, which showed that mass warped four-dimensional space-time.
Since were unable to perceive these four dimensions, we attribute motion in the presence of a massive body, such as a planet, not to this curvature but to a force of gravity. Could the other force known at the time (the electromagnetic force) be explained by the curvature of an extra dimension of space?
Kaluza and Klein found it could. But since the electromagnetic force was 1,040 times stronger than gravity, the curvature of the extra dimension had to be so great that it was rolled up much smaller than an atom and would be impossible to notice. When a particle such as an electron travelled through space, invisible to us, it would be going round and round the fifth dimension, like a hamster in a wheel.
Kaluza and Kleins five-dimensional theory was dealt a serious blow by the discovery of two more fundamental forces that operated in the realm of the atomic nucleus: the strong and weak nuclear forces.
But the idea that extra dimensions explain forces was revived half a century later by proponents of string theory, which views the fundamental building blocks of the Universe not as particles, but tiny strings of mass-energy. To mimic all four forces, the strings vibrate in 10-dimensional space-time, with six space dimensions rolled up far smaller than an atom.
String theory gave rise to the idea that our Universe might be a three-dimensional island, or brane, floating in 10-dimensional space-time. This raised the intriguing possibility of explaining why gravity is so extraordinarily weak compared with the other three fundamental forces. While the forces are pinned to the brane, goes the idea, gravity leaks out into the six extra space dimensions, enormously diluting its strength on the brane.
There is a way to have a bigger fifth dimension, which is curved in such a way that we dont see it, and this was suggested by the physicists Lisa Randall and Raman Sundrum in 1999. An extra space dimension might even explain one of the great cosmic mysteries: the identity of dark matter, the invisible stuff that appears to outweigh the visible stars and galaxies by a factor of six.
In 2021, a group of physicists from Johannes Gutenberg University in Mainz, Germany, proposed that the gravity of hitherto unknown particles propagating in a hidden fifth dimension could manifest itself in our four-dimensional Universe as the extra gravity we currently attribute to dark matter.
Though an exciting possibility, its worth pointing out that theres no shortage of possible candidates for dark matter, including subatomic particles known as axions, black holes and reverse-time matter from the future!
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Living by the week – The Times of India Blog
The basic unit of work done, revenues, penalties are universally calculated by a seven-day tenure, or the week. Almost universal across al religions, -scriptures, Holy books of any sect, Th Bible, sub-sets of Christianity ancient Hindu scriptures.
As a trend, it starts with a sabbath, the Sunday, generally a day of rest, prayers and planning for the remaining days of the week.
The quantum of seven days, was respected, whether they knew if the Earth went round the Sun, or the Sun went round the Earth.
There might have been numerous eclipses with various protocols, but the seven -day protocol remained the same!
Unimaginable, that there was a fixed constant even before quantum physics, and science never found a hurdle in it. If a satellite was to be launched, choose the day of the week. You may avoid a Sunday, but the rest of this seven day slot remains the same.
Post-,Covid, your schedules, lifestyles, mental solace may or not have altered. On Wednesday, your digital friend, the mobile, flashes that you have just one more day to pay, or you are sort of cut-off from the world.
A bit of digression here. This could be your way to the Covid lane. India has concerns of a restrained pandemic, that may threaten anytine. Where as packed food has standards compatible with Covid norms. It is the bare hand contact that spreads the disease. Stricter norms need to be enforced here. Costs of packing may go up by Rs 20, but keeps the wolf out of the door.
I would not know how the other days passed by, possibly taking half decisions on your schedule.
The weekend is where the stakes lie. Revenues, pats from the boss, but the compelling Zoom Meeting was cancelled on account of cost cutting.
Wait another week. Youll get used to it!
Sarhaney Mir key ahista bolo.Ki abhi tuk rotey, rotey so gaya
(Speak softly near Mirs bed.For he just slept after much sobbing)
Views expressed above are the author's own.
END OF ARTICLE
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‘Need for Space’: How Have Humans Benefited From Exploration of the Universe? – News18
NASA has sometimes been scrutinized for spending billions of dollars on space exploration and travel. The argument goes like this, why do we need to spend billions of dollars and the energy of the most creative people on space explorations when we can actually send that capital and mental energy to solve problems on Earth.
According to a Space News report, an opinion poll on completing 50 years since Man stepped on Moon revealed that only 27% of people think that expeditions to Mars are important.
By the looks of it, it does look like a valid, well-intentioned argument. However, there are glaring gaps in it, which brings it to the brink of being an absurd question. In reality, space explorations and space-related research have immensely benefitted people on Earth.
Be it technology, medicine, health, roads, shoes, NASAs research projects have given birth to numerous tools and techniques that have made peoples lives easier than ever.
Neil DeGrasse Tyson, the famous astrophysicist, once extensively discussed the same argument in a podcast with Joe Rogan. He claimed that the third of the worlds GDP comes from computing and the Information Technology sector, the origin of which could be traced back to Quantum Physics, discovered in the 1920s.
He then mentions about one of his professors, who was an avid observer of the universe. He was researching on detection of gas clouds between stars, which led him to discover a new phenomenon in Physics called Nuclear Magnetic Resonance.
This phenomenon, when came under the observation of a medical technologist, gave birth to the Magnetic Resonance Imager (MRI), which is one of the most important inventions in medical science. This goes on to prove how exploring space, which, to a layman taxpayer, looks trivial, holds utmost significance.
Technologies like GPS, power tools, things like athletic shoes, memory foam, scratch-resistant glass, smoke detectors, and safety grooves on roads all came from space-related researches.
Space not only solves the problems of the present but also maps the road to solutions to future problems. Do you still think space exploration is a waste of capital and human energy?
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'Need for Space': How Have Humans Benefited From Exploration of the Universe? - News18
Quantum of solace: even physicists are still scratching their heads – The Guardian
Your editorial on quantum physics (30 August) starts with a quote from Richard Feynman nobody understands quantum mechanics and then says that is no longer true. One of us (Norman Dombey) was taught quantum theory by Feynman at Caltech; the other (John Charap) was taught by Paul Dirac at Cambridge. Quantum theory was devised by several physicists including Dirac, Erwin Schrdinger and Werner Heisenberg in the 1920s and 1930s, and Dirac made their work relativistic.
It is absurd to say that quantum mechanics is now understood whereas it was not 50 years ago. There have of course been advances in our understanding of quantum phenomena, but the conceptual framework of quantum physics remains as it was. The examples you give of nuclear plants, medical scans and lasers involve straightforward applications of quantum mechanics that were understood 50 years ago.
The major advance in the understanding of quantum physics in this period is a theorem of John Bell from Cern, which states that quantum physics cannot be local that is to say that it permits phenomena to be correlated at arbitrarily large distances from each other. This has now been demonstrated experimentally and leads to what is known as quantum entanglement, which is important in the development of quantum computers. But even these ideas were discussed by Albert Einstein and coworkers in 1935.
The editorial goes on to say that subatomic particles do not travel a path that can be plotted. If that were so, how can protons travel at the Large Hadron Collider at Cern and hit their target so that experiments can be performed?
We agree with Phillip Ball, who wrote in Physics World that quantum mechanics is still, a century after it was conceived, making us scratch our heads. There are many speculative proposals in contention but none have consensus support. John Charap Emeritus professor of theoretical physics, Queen Mary University of London; Norman Dombey Emeritus professor of theoretical physics, University of Sussex
Whoever wrote this editorial does not understand what Richard Feynman meant when he said that nobody really understands quantum mechanics. Being able to make a smartphone, a nuclear weapon or an MRI machine does not require understanding quantum mechanics in the sense he meant it requires the physical chops to set up the equations and the mathematical chops to find or approximate solutions to them. Any competent physicist has been able to do those calculations for at least 50 years. What Feynman meant was that, for quantum mechanics, nobody has the kind of intuitive understanding of what is actually happening in the world that physicists seek to gain. All we can do is shut up and calculate, or get lost in a never-never land of competing but empirically equivalent interpretations.
Perhaps Carlo Rovellis relational interpretation of quantum mechanics provides the intuitive understanding wed like to have, although I rather doubt it, and I dont believe Rovelli claims it does. Perhaps it even makes testable predictions that could distinguish it from other interpretations and thus is science rather than philosophy (I have no objection to philosophy).
It is just as true today as it was when Feynman said it in 1964 that nobody (or almost nobody) really understands quantum mechanics. And now, as then, a competent physicist does not need the kind of understanding Feynman meant to use the theory. Indeed, theres no strong reason to believe that the human mind should be equipped to understand it at all. To quote another famous physicist: this editorial is not even wrong.Tim BradshawNorth Tawton, Devon
While its highly probable that the position of my copy of Helgoland is where I shelved it, I wont know whether its pages are printed or blank until I get round to reading it. However, from Prof Rovellis previous work, I agree the fundamental truth is that its impossible to know everything about the world, including whether this letter will be published and in what world.Harold MozleyYork
Given your editorial on quantum physics, is the strapline now facts are relatively sacred or facts are sacred but relative?Simon TaylorWarwick, Warwickshire
Have an opinion on anything youve read in the Guardian today? Please email us your letter and it will be considered for publication.
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Quantum of solace: even physicists are still scratching their heads - The Guardian
Would Doctor Strange think of using a quantum crystal to reveal the secrets of dark matter? – SYFY WIRE
Doctor Strange already has the Time Stone, but if he lived in our universe, he would probably be after a quantum crystal. So maybe it cant transport you through space and time or be worn in a necklace that looks like mesmerizing cosmic eye.
What would make quantum crystal desirable even in the Marvel universe is its hypersensitivity, since it can pick up on such faint electromagnetic signals that it might detect dark matter particles, or axions, in the future. That means it could prove the existence of (still hypothetical) dark matter. Magic? More like quantum mechanics.
There was just one issue with transforming an ordinary beryllium crystal into something borderline paranormal. Quantum noise was in the way. Researcher Diego Barbarena and his colleagues, led by atomic physicist Ana Maria Rey of JILA, realized that quantum entanglement was the only way out.
Creation of quantum entanglement between our system and our probe allowed us to avoid the effects of the noise on our readout and hence we end up with just the signal, he told SYFY WIRE. Entanglement allows us to avoid some of the sources of noise present on our system.
Quantum entanglement of two particles means that they will do the same thing simultaneously no matter how far away they are from each other. This is the same idea behind Hawking radiation, in which one entangled particle escapes a black hole while the other falls in. It is thought that the escaped particle may be able to tell us what actually happens inside a black hole. Entanglement gets around of the Heisenberg Uncertainty Principle, which claims that the more precision you observe a particle with, the less you will find out less about its properties.
Creating a quantum crystal involved using a system of electrodes and magnetic fields to trap beryllium ions and prevent their usual tendency to try to repel each other. Without that repulsion, the atoms arranged themselves into a thin, flat crystal. The motions of the beryllium ions were entangled with their spins. Because the beryllium atoms were now able to move as a whole when they felt a signal, the entire crystal would vibrate.
So what makes this crystal so hypersensitive, which would be highly desirable for a superhero who is constantly breaking the laws of physics?
The crystal consists of many ions, which like to move in an oscillatory fashion with a certain natural frequency, Barbarena said. If you hit it with something that oscillates at that same frequency the effect on the motion is going to be greater than if you hit it with something oscillating at a lower or higher frequency.
Another reason this quantum crystal can pick up on such low frequencies is the amount of ions it has. The crystals 150 ions to make it seem as if its responses are being measured as many times. Because the thing being measured is the motion of the crystal in response to an electromagnetic signal, and a signal affects the ion spin entangled with it, the researchers were looking for signals that oscillated at the same frequency as the ions. This is the resonance conditionwhen a signal and a detector are moving at the same frequency.
By turning on that magnetic field, and assuming axions are present, an electric field signal would be automatically generated, said Barbarena.
At least hypothetically, detecting dark matter would mean that axions would have to morph into photons when they ran into a magnetic field. Axions are believed to create an invisible mass rather than just float around as individual particles. This is why scientists think that entire globs of dark matter exist, but dark matter is supposedly extremely light, so it helps having something that can pick up the faintest signals. This crystal is already ten times more sensitive than anything else, and if axions did turn into photons, it would probably find them.
You can probably imagine how useful this would be for Doctor Strange trying to sense enemies on the prowl, so long as they gave off some sort of electromagnetic signal.
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Physics – 3D Collimation of Matter Waves – Physics
August 30, 2021• Physics 14, 119
An innovative matter-wave lens exploiting atomic interactions is able to slow the expansion of a Bose-Einstein condensate in three dimensions, thus reaching unprecedented ultralow temperatures.
At ultralow temperatures, dilute atomic gases manifest their full quantum nature as matter waves in the form of Bose-Einstein condensates (BECs). Through the interference of matter waves in an interferometer, researchers can probe gravitational effects at microscopic scales and thereby test gravity at the quantum level. But improving the precision of these tests requires lowering the temperature of the BECs even further. Ernst Rasel from Leibniz University Hannover in Germany and colleagues have realized BECs at the lowest temperature so far (38 pK) by collimating the atoms in 3D with a new time-domain lens system based on atomic interactions [1].
The team prepared BEC matter waves with over one hundred thousand atoms and recorded their time evolution via absorption imaging during 2 s of free fall in a 110-m-high tower. Without any lensing applied, the BEC expanded through random thermal motion and became too dilute to be detected after 160 ms. In contrast, when the team collimated the atoms with their lens, the expansion slowed, and the BEC was visible throughout its fall. Moreover, the authors extrapolated their results and found that their innovative collimation technique can generate slowly expanding BECs that should remain detectable even after 17 s, which could be useful in future tests of gravity in space-based experiments.
BEC matter waves are a magnificent tool with which to explore the interface between quantum theory and general relativitythe underlying theories of the microcosmos and the macrocosmos, respectively. When a BEC is placed in an interferometer, its interference pattern will partly depend on gravitational effects due to the mass of the atoms. Detecting these effects could allow for fundamental tests, such as the verification of the Einstein equivalence principle with quantum objects. These tests require letting the BEC freely evolve for long times, which poses a problem, as the atoms tend to fly apart because of the internal kinetic energy (or temperature) of the system. Reducing this energy would extend the expansion time before the BEC becomes too dilute and improve the precision of matter-wave interferometry.
A powerful way to reduce a BECs internal kinetic energy is to exploit a matter-wave lens to focus the BEC atoms at infinity. Standard matter-wave lenses that are based on magnetic, optical, or electrostatic forces have indeed been used to reduce the BEC internal kinetic energy. Those tools can reach effective temperatures of about 50 pK but, unfortunately, only in two dimensions [2]. A magnetic lens, for example, has a cylindrical geometry that can bend the trajectory of atoms inward along the two radial directions, but it lacks this refractive power along the axial direction.
In their experiments, Rasel and colleagues achieve an unprecedently low temperature of 38 pK by exploiting an innovative matter-wave lens system in the time domain. Such a system can focus the BEC wave at infinity in all three spatial dimensions by cleverly combining both a magnetic lens and a collective-mode excitation (or shape vibration) in the BEC [3].
The team first generated a BEC of approximately one hundred thousand rubidium atoms within a cylindrically shaped magnetic trap produced on a microchip [4]. To excite the collective-mode oscillation, the researchers quickly reduced the trap magnetic bias field along one direction, while increasing the trapping strength in the other two directions. Because of the atomic interactions, the BEC responded by lengthening along its axis and slimming around the waist (Fig. 1). If allowed to continue this oscillation, the BEC would return to its original shape, but the researchers instead released the BEC at the time of maximum slimming. This was the key step for achieving 3D collimation, as it minimized the expansion along the axial direction. To slow the expansion around the BECs waist, the team applied a magnetic lens that collimated the atomic motion in the other two dimensions.
The experiments were performed at the Bremen drop tower in Germany, which provides an exceptional microgravity environment with residual accelerations of the order of 106g [5]. The researchers released the BEC at the top of the tower and measured its size via absorption imaging at different points during the free fall. From the data, they surmised that the expansion velocities were of the order of 60ms. In simulations, the team extended the free-fall time and showed that the BEC should remain detectable for up to 17 s.
By tuning both the oscillation time at the condensates release and the strength of the magnetic lenss potential, this new lensing method offers the possibility to engineer and control BEC shape and expansion for fundamental physics tests as well as for quantum sensing technologies. Indeed, the ability to generate slowly expanding BECs for tens of seconds can enable high-precision gravitational-wave detection [6], measurements of the gravitational constant [7] and the tidal force of gravity [8], as well as the search for ultralight dark matter [9] and a stringent quantum verification of Einsteins equivalence principle, both in drop towers and in space [10].
Furthermore, the 3D matter-wave lens system introduced by Rasel and co-workers provides a new and exciting perspective on the quantum advantage hidden behind the presence of interatomic interactions, often viewed as a drawback in matter-wave optics with long expansion times. Indeed, such interactions can be exploited as a powerful metrological tool in the development of matter-wave quantum sensors, enabling not only high-coherence properties but also highly nonclassical correlations.
Vincenzo Tamma is currently the Founding Director of the Quantum Science and Technology Hub and a reader in physics at the University of Portsmouth, UK, after being a group leader at the Institute of Quantum Physics at Ulm University, Germany. His Ph.D. research at the University of Maryland, Baltimore County and at the University of Bari Aldo Moro, Italy, was recognized with the Giampietro Puppi Award for the best Italian Ph.D. thesis in physics and astrophysics in 20072009. His research aims for a deeper understanding of the fundamental physics at the interface of quantum mechanics, quantum information, complexity theory, atomic physics, and general relativity, as well as at boosting the real-world implementation of quantum-enhanced technologies for computing and sensing applications.
Christian Deppner, Waldemar Herr, Merle Cornelius, Peter Stromberger, Tammo Sternke, Christoph Grzeschik, Alexander Grote, Jan Rudolph, Sven Herrmann, Markus Krutzik, Andr Wenzlawski, Robin Corgier, Eric Charron, David Gury-Odelin, Naceur Gaaloul, Claus Lmmerzahl, Achim Peters, Patrick Windpassinger, and Ernst M. Rasel
Phys. Rev. Lett. 127, 100401 (2021)
Published August 30, 2021
Researchers demonstrate lighter, smaller optics and vacuum components for cold-atom experiments that they hope could enable the development of portable quantum technologies. Read More
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Making OLED Displays In The Home Lab – Hackaday
Just a general observation: when your projects BOM includes ytterbium metal, chances are pretty good that its something interesting. Wed say that making your own OLED displays at home definitely falls into that category.
Of course, the making of organic light-emitting diodes requires more than just a rare-earth metal, not least of which is the experience in the field that [Jeroen Vleggaar] brings to this project. Having worked on OLEDs at Philips for years, [Jeroen] is well-positioned to tackle the complex process, involving things like physical vapor deposition and the organic chemistry of coordinated quinolones. And thats not to mention the quantum physics of it all, which is nicely summarized in the first ten minutes or so of the video below. From there its all about making a couple of OLED displays using photolithography and the aforementioned PVD to build up a sandwich of Alq3, an electroluminescent organic compound, on a substrate of ITO (indium tin oxide) glass. We especially appreciate the use of a resin 3D printer to create the photoresist masks, as well as the details on the PVD process.
The displays themselves look fantastic at least for a while. The organic segments begin to oxidize rapidly from pinholes in the material; a cleanroom would fix that, but this was just a demonstration, after all. And as a bonus, the blue-green glow of [Jeroen]s displays reminds us strongly of the replica Apollo DSKY display that [Ben Krasnow] built a while back.
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Ask Ethan: What Impact Could Magnetic Monopoles Have On The Universe? – Forbes
Electromagnetic fields as they would be generated by positive and negative electric charges, both at ... [+] rest and in motion (top), as well as those that would theoretically be created by magnetic monopoles (bottom), were they to exist.
Out of all of the known particles both fundamental and composite there are a whole slew of properties that emerge. Each individual quantum in the Universe can have a mass, or they can be massless. They can have a color charge, meaning they couple to the strong force, or they can be chargeless. They can have a weak hypercharge and/or weak isospin, or they can be completely decoupled from the weak interactions. They can have an electric charge, or they can be electrically neutral. They can have a spin, or an intrinsic angular momentum, or they can be spinless. And if you have both an electric charge and some form of angular momentum, youll also have a magnetic moment: a magnetic property that behaves as a dipole, with a north end and a south end.
But there are no fundamental entities that have a unique magnetic charge, like a north pole or south pole by itself. This idea, of a magnetic monopole, has been around for a long time as a purely theoretical construct, but there are reasons to take it seriously as a physical presence in our Universe. Patreon supporter Jim Nance writes in because he wants to know why:
You've talked in the past about how we know the universe didn't get arbitrarily hot because we don't see relics like magnetic monopoles.You say that with a lot of confidence which makes me wonder, given that no one has ever seen a magnetic monopole or any of the other relics, why are we confident that they exist?
Its a deep question that demands an in-depth answer. Lets start at the beginning: going all the way back to the 19th century.
When you move a magnet into (or out of) a loop or coil of wire, it causes the field to change around ... [+] the conductor, which causes a force on charged particles and induces their motion, creating a current. The phenomena are very different if the magnet is stationary and the coil is moved, but the currents generated are the same. This was the jumping-off point for the principle of relativity.
A little bit was known about electricity and magnetism at the start of the 1800s. It was generally recognized that there was such a thing as electric charge, that it came in two types, where like charges repelled and opposite charges attracted, and that electric charges in motion created currents: what we know as electricity today. We also knew about permanent magnets, where one side acted like a north pole and the other side like a south pole. However, if you broke a permanent magnet in two, no matter how small you chopped it up, youd never wind up with a north pole or a south pole by itself; magnetic charges only came paired up in a dipole configuration.
Throughout the 1800s, a number of discoveries took place that helped us make sense of the electromagnetic Universe. We learned about induction: how moving electric charges actually generate magnetic fields, and how changing magnetic fields, in turn, induce electric currents. We learned about electromagnetic radiation, and how accelerating electric charges can emit light of various wavelengths. And when we put all of our knowledge together, we learned that the Universe wasnt symmetric between electric and magnetic fields and charges: Maxwells equations only possess electric charges and currents. There are no fundamental magnetic charges or currents, and the only magnetic properties we observe come about as being induced by electric charges and currents.
It's possible to write down a variety of equations, like Maxwell's equations, that describe the ... [+] Universe. We can write them down in a variety of ways, but only by comparing their predictions with physical observations can we draw any conclusion about their validity. It's why the version of Maxwell's equations with magnetic monopoles (right) don't correspond to reality, while the ones without (left) do.
Mathematically or if you prefer, from a theoretical physics perspective its very easy to modify Maxwells equations to include magnetic charges and currents: where you simply add in the ability for objects to also possess a fundamental magnetic charge: an individual north or south pole inherent to an object itself. When you introduce those extra terms, Maxwells equations get a modification, and become completely symmetric. All of a sudden, induction now works the other way as well: moving magnetic charges would generate electric fields, and a changing electric field can induce a magnetic current, causing magnetic charges to move and accelerate within a material that can carry a magnetic current.
All of this was simply fanciful consideration for a long time, until we started to recognize the roles that symmetries play in physics, and the quantum nature of the Universe. Its eminently possible that electromagnetism, at some higher energy state, was symmetric between electric and magnetic components, and that we live in a low-energy, broken symmetry version of that world. Although Pierre Curie, in 1894, was one of the first to point out that magnetic charges could exist, it was Paul Dirac, in 1931, who showed something remarkable: that if you had even one magnetic charge, anywhere in the Universe, then it quantum mechanically implied that electric charges should be quantized everywhere.
The difference between a Lie algebra based on the E(8) group (left) and the Standard Model (right). ... [+] The Lie algebra that defines the Standard Model is mathematically a 12-dimensional entity; the E(8) group is fundamentally a 248-dimensional entity. There is a lot that has to go away to get back the Standard Model from String Theories as we know them.
This is fascinating, because not only are electric charges observed to be quantized, but theyre quantized in fractional amounts when it comes to quarks. In physics, one of the most powerful hints we have that new discoveries might be around the corner are by discovering a mechanism that could explain why the Universe has the properties we observe it to have.
However, none of that provides any evidence that magnetic monopoles actually do exist, it simply suggests that they might. On the theoretical side, quantum mechanics was soon superseded by quantum field theory, where the fields are also quantized. To describe electromagnetism, a gauge group known as U(1) was introduced, and this is still used at the present. In gauge theory, the fundamental charges associated with electromagnetism will be quantized only if the gauge group, U(1), is compact; if the U(1) gauge group is compact, however, we get magnetic monopoles anyway.
Again, there might turn out to be a different reason why electric charges have to be quantized, but it seemed at least with Diracs reasoning and what we know about the Standard Model that theres no reason why magnetic monopoles shouldnt exist.
This diagram displays the structure of the standard model (in a way that displays the key ... [+] relationships and patterns more completely, and less misleadingly, than in the more familiar image based on a 4x4 square of particles). In particular, this diagram depicts all of the particles in the Standard Model (including their letter names, masses, spins, handedness, charges, and interactions with the gauge bosons: i.e., with the strong and electroweak forces). It also depicts the role of the Higgs boson, and the structure of electroweak symmetry breaking, indicating how the Higgs vacuum expectation value breaks electroweak symmetry, and how the properties of the remaining particles change as a consequence.
For many decades, even after numerous mathematical advances, the idea of magnetic monopoles remained only a curiosity that hung around in the back of theorists minds, without any substantial progress being made. But in 1974, a few years after we recognized the full structure of the Standard Model which in group theory, is described by SU(3) SU(2) U(1) physicists started to entertain the idea of unification. While, at low energies, SU(2) describes the weak interaction and U(1) describes the electromagnetic interaction, they actually unify at energies of around ~100 GeV: the electroweak scale. At those energies, the combined group SU(2) U(1) describes the electroweak interactions, and those two forces unify.
Is it possible, then, that all of the fundamental forces unify into some larger structure at high energies? They might, and thus the idea of Grand Unified Theories began to come about. Larger gauge groups, like SU(5), SO(10), SU(6), and even exceptional groups began to be considered. Almost immediately, however, a number of unsettling but exciting consequences began to emerge. These Grand Unified Theories all predicted that the proton would be fundamentally stable and would decay; that new, super-heavy particles would exist; and that, as shown in 1974 by both Gerard tHooft and Alexander Polyakov, they would lead to the existence of magnetic monopoles.
The concept of a magnetic monopole, emitting magnetic field lines the same way an isolated electric ... [+] charge would emit electric field lines. Unlike magnetic dipoles, there's only a single, isolated source, and it would be an isolated north or south pole with no counterpart to balance it out.
Now, we have no proof that the ideas of grand unification are relevant for our Universe, but again, its possible that they do. Whenever we consider a theoretical idea, one of the things we look for are pathologies: reasons that whatever scenario were interested in would break the Universe in some way or another. Originally, when tHooft-Polyakov monopoles were proposed, one such pathology was discovered: the fact that magnetic monopoles would do something called overclose the Universe.
In the early Universe, things are hot and energetic enough that any particle-antiparticle pair you can create with enough energy via Einsteins E = mc2 will get created. When you have a broken symmetry, you can either give a non-zero rest mass to a previously massless particle, or you can spontaneously rip copious numbers of particles (or particle-antiparticle pairs) out of the vacuum when the symmetry breaks. An example of the first case is what happens when the Higgs symmetry breaks; the second case could occur, for example, when the Peccei-Quinn symmetry breaks, pulling axions out of the quantum vacuum.
In either case, this could lead to something devastating.
If the Universe had just a slightly higher matter density (red), it would be closed and have ... [+] recollapsed already; if it had just a slightly lower density (and negative curvature), it would have expanded much faster and become much larger. The Big Bang, on its own, offers no explanation as to why the initial expansion rate at the moment of the Universe's birth balances the total energy density so perfectly, leaving no room for spatial curvature at all and a perfectly flat Universe. Our Universe appears perfectly spatially flat, with the initial total energy density and the initial expansion rate balancing one another to at least some 20+ significant digits. We can be certain that the energy density didn't spontaneously increase by large amounts in the early Universe by the fact that it hasn't recollapsed.
Normally, the Universe expands and cools, with the overall energy density being closely related to the rate of expansion at any point in time. If you either take a large number of previously massless particles and give them a non-zero mass, or you suddenly and spontaneously add a large number of massive particles to the Universe, you rapidly increase the energy density. With more energy present, suddenly the expansion rate and the energy density are no longer in balance; theres too much stuff in the Universe.
This causes the expansion rate to not only drop, but in the case of monopole production, to plummet all the way to zero, and then to begin contracting. In short order, this leads to a recollapse of the Universe, ending in a Big Crunch. This is called overclosing the Universe, and cannot be an accurate description of our reality; were still here and things havent recollapsed. This puzzle was known as the monopole problem, and was one of the three main motivations for cosmic inflation.
Just as inflation stretches the Universe, whatever its geometry was previously, to a state indistinguishable from flat (solving the flatness problem), and imparts the same properties everywhere to all locations within our observable Universe (solving the horizon problem), so long as the Universe never heats back up to above the grand unification scale after inflation ends, it can solve the monopole problem, too.
If the Universe inflated, then what we perceive as our visible Universe today arose from a past ... [+] state that was all causally connected to the same small initial region. Inflation stretched that region to give our Universe the same properties everywhere (top), made its geometry appear indistinguishable from flat (middle), and removed any pre-existing relics by inflating them away (bottom). So long as the Universe never heats back up to high enough temperatures to produce magnetic monopoles anew, we will be safe from overclosure.
This was understood way back in 1980, and the combined interest in tHooft-Polyakov monopoles, grand unified theories, and the earliest models of cosmic inflation led some people to embark on a remarkable undertaking: to try and experimentally detect magnetic monopoles. In 1981, experimental physicist Blas Cabrera built a cryogenic experiment involving a coil of wire, explicitly designed to search for magnetic monopoles.
By building a coil with eight loops in it, he reasoned that if a magnetic monopole ever passed through the coil, hed see a specific signal due to the electric induction that would occur. Just like passing one end of a permanent magnet into (or out of) a coil of wire will induce a current, passing a magnetic monopole through that coil of wire should induce not only an electric current, but an electric current that corresponds to exactly 8 times the theoretical value of the magnetic monopoles charge, owing to the 8 loops in his experimental setup. (If a dipole were to pass through, instead, there would be a signal of +8 followed shortly after by a signal of -8, allowing the two scenarios to be differentiated.)
On February 14, 1982, no one was in the office monitoring the experiment. The next day, Cabrera came back, and was shocked at what he observed. The experiment had recorded a single signal: one corresponding almost exactly to the signal a magnetic monopole ought to produce.
In 1982, an experiment running under the leadership of Blas Cabrera, one with eight turns of wire, ... [+] detected a flux change of eight magnetons: indications of a magnetic monopole. Unfortunately, no one was present at the time of detection, and no one has ever reproduced this result or found a second monopole. Still, if string theory and this new result are correct, magnetic monopoles, being not forbidden by any law, must exist at some level.
This set off a tremendous interest in the endeavor. Did it mean inflation was wrong, and we really did have a Universe with magnetic monopoles? Did it mean that inflation was correct, and the one (at most) monopole that should remain in our Universe happened to pass through Cabreras detector? Or did it means that this was the ultimate in experimental errors: a glitch, a prank, or something else that we couldnt explain, but was spurious?
A number of copycat experiments ensued, many of which were larger, ran for longer times, and had greater numbers of loops in their coils, but no one else ever saw anything that resembled a magnetic monopole. On February 14, 1983, Stephen Weinberg wrote a Valentines Day poem to Cabrera, which read:
Roses are red,
Violets are blue,
Its time for monopole
Number TWO!
But despite all the experiments weve ever run, including some that have continued to the present day, there have been no other signs of magnetic monopoles ever seen. Cabrera himself went on to lead numerous other experiments, but we may never know what truly happened on that day in 1982. All we know is that, without the ability to confirm and reproduce that result, we cannot claim that we have direct evidence for the existence of magnetic monopoles.
These are the modern constraints available, from a variety of experiments largely driven from ... [+] neutrino astrophysics, that place the tightest bounds on the existence and abundance of magnetic monopoles in the Universe. The current bound is many orders of magnitude below the expected abundance if Cabrera's 1982 detection was normal, rather than an outlier.
Theres so much that we dont know about the Universe, including what happens at energies far in excess of what we can observe in the collisions that take place at the Large Hadron Collider. We dont know whether, at some high energy scale, the Universe can actually produce magnetic monopoles; we simply know that at the energies we can probe, we havent seen them. We dont know whether grand unification is a property of our Universe in the earliest stages, but we do know this much: whatever occurred early on, it didnt overclose the Universe, and it didnt fill our Universe with these leftover, high-energy relics from a hot, dense state.
Does our Universe, at some level, admit the existence of magnetic monopoles? Thats not a question we can presently answer. What we can state with confidence, however is the following:
Its nearly 40 years since the one experimental clue hinting at the possible existence of magnetic monopoles simply dropped into our lap. Until a second clue comes along, however, all well be able to do is tighten our constraints on where these hypothetical monopoles arent allowed to be hiding.
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Ask Ethan: What Impact Could Magnetic Monopoles Have On The Universe? - Forbes