Abstract artists concept of neutrino particles.

Physicists are closing in on the true nature of the neutrino and might be closer to answering a fundamental question about our own existence.

In a Laboratory under a mountain, physicists are using crystals far colder than frozen air to study ghostly particles, hoping to learn secrets from the beginning of the universe. Researchers at the Cryogenic Underground Observatory for Rare Events (CUORE) announced this week that they had placed some of the most stringent limits yet on the strange possibility that the neutrino is its own antiparticle. Neutrinos are deeply unusual particles, so ethereal and so ubiquitous that they regularly pass through our bodies without us noticing. CUORE has spent the last three years patiently waiting to see evidence of a distinctive nuclear decay process, only possible if neutrinos and antineutrinos are the same particle. CUOREs new data shows that this decay doesnt happen for trillions of trillions of years, if it happens at all. CUOREs limits on the behavior of these tiny phantoms are a crucial part of the search for the next breakthrough in particle and nuclear physics and the search for our own origins.

CUORE scientists Dr. Paolo Gorla (LNGS, left) and Dr. Lucia Canonica (MIT, right) inspect the CUORE cryogenic systems. Credit: Yury Suvorov and the CUORE Collaboration

Ultimately, we are trying to understand matter creation, said Carlo Bucci, researcher at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy and the spokesperson for CUORE. Were looking for a process that violates a fundamental symmetry of nature, added Roger Huang, a postdoctoral researcher at the Department of Energys Lawrence Berkeley National Laboratory (Berkeley Lab) and one of the lead authors of the new study.

CUORE Italian for heart is among the most sensitive neutrino experiments in the world. The new results from CUORE are based on a data set ten times larger than any other high-resolution search, collected over the last three years. CUORE is operated by an international research collaboration, led by the Istituto Nazionale di Fisica Nucleare (INFN) in Italy and Berkeley Lab in the US. The CUORE detector itself is located under nearly a mile of solid rock at LNGS, a facility of the INFN. U.S. Department of Energy-supported nuclear physicists play a leading scientific and technical role in this experiment. CUOREs new results were published on April 6, 2022, in Nature.

Neutrinos are everywhere there are trillions of neutrinos passing through your thumbnail alone as you read this sentence. They are invisible to the two strongest forces in the universe, electromagnetism and the strong nuclear force, which allows them to pass right through you, the Earth, and nearly anything else without interacting. Despite their vast numbers, their enigmatic nature makes them very difficult to study, and has left physicists scratching their heads ever since they were first postulated over 90 years ago. It wasnt even known whether neutrinos had any mass at all until the late 1990s as it turns out, they do, albeit not very much.

One of the many remaining open questions about neutrinos is whether they are their own antiparticles. All particles have antiparticles, their own antimatter counterpart: electrons have antielectrons (positrons), quarks have antiquarks, and neutrons and protons (which make up the nuclei of atoms) have antineutrons and antiprotons. But unlike all of those particles, its theoretically possible for neutrinos to be their own antiparticles. Such particles that are their own antiparticles were first postulated by the Italian physicist Ettore Majorana in 1937, and are known as Majorana fermions.

CUORE detector being installed into the cryostat. Credit: Yury Suvorov and the CUORE Collaboration

If neutrinos are Majorana fermions, that could explain a deep question at the root of our own existence: why theres so much more matter than antimatter in the universe. Neutrinos and electrons are both leptons, a kind of fundamental particle. One of the fundamental laws of nature appears to be that the number of leptons is always conserved if a process creates a lepton, it must also create an anti-lepton to balance it out. Similarly, particles like protons and neutrons are known as baryons, and baryon number also appears to be conserved. Yet if baryon and lepton numbers were always conserved, then there would be exactly as much matter in the universe as antimatter and in the early universe, the matter and antimatter would have met and annihilated, and we wouldnt exist. Something must violate the exact conservation of baryons and leptons. Enter the neutrino: if neutrinos are their own antiparticles, then lepton number wouldnt have to be conserved, and our existence becomes much less mysterious.

The matter-antimatter asymmetry in the universe is still unexplained, said Huang. If neutrinos are their own antiparticles, that could help explain it.

Nor is this the only question that could be answered by a Majorana neutrino. The extreme lightness of neutrinos, about a million times lighter than the electron, has long been puzzling to particle physicists. But if neutrinos are their own antiparticles, then an existing solution known as the seesaw mechanism could explain the lightness of neutrinos in an elegant and natural way.

But determining whether neutrinos are their own antiparticles is difficult, precisely because they dont interact very often at all. Physicists best tool for looking for Majorana neutrinos is a hypothetical kind of radioactive decay called neutrinoless double beta decay. Beta decay is a fairly common form of decay in some atoms, turning a neutron in the atoms nucleus into a proton, changing the chemical element of the atom and emitting an electron and an anti-neutrino in the process. Double beta decay is more rare: instead of one neutron turning into a proton, two of them do, emitting two electrons and two anti-neutrinos in the process. But if the neutrino is a Majorana fermion, then theoretically, that would allow a single virtual neutrino, acting as its own antiparticle, to take the place of both anti-neutrinos in double beta decay. Only the two electrons would make it out of the atomic nucleus. Neutrinoless double-beta decay has been theorized for decades, but its never been seen.

The CUORE experiment has gone to great lengths to catch tellurium atoms in the act of this decay. The experiment uses nearly a thousand highly pure crystals of tellurium oxide, collectively weighing over 700 kg. This much tellurium is necessary because on average, it takes billions of times longer than the current age of the universe for a single unstable atom of tellurium to undergo ordinary double beta decay. But there are trillions of trillions of atoms of tellurium in each one of the crystals CUORE uses, meaning that ordinary double beta decay happens fairly regularly in the detector, around a few times a day in each crystal. Neutrinoless double beta decay, if it happens at all, is even more rare, and thus the CUORE team must work hard to remove as many sources of background radiation as possible. To shield the detector from cosmic rays, the entire system is located underneath the mountain of Gran Sasso, the largest mountain on the Italian peninsula. Further shielding is provided by several tons of lead. But freshly mined lead is slightly radioactive due to contamination by uranium and other elements, with that radioactivity decreasing over time so the lead used to surround the most sensitive part of CUORE is mostly lead recovered from a sunken ancient Roman ship, nearly 2000 years old.

Perhaps the most impressive piece of machinery used at CUORE is the cryostat, which keeps the detector cold. To detect neutrinoless double beta decay, the temperature of each crystal in the CUORE detector is carefully monitored with sensors capable of detecting a change in temperature as small as one ten-thousandth of a Celsius degree. Neutrinoless double beta decay has a specific energy signature and would raise the temperature of a single crystal by a well-defined and recognizable amount. But in order to maintain that sensitivity, the detector must be kept very cold specifically, its kept around 10 mK, a hundredth of a degree above absolute zero. This is the coldest cubic meter in the known universe, said Laura Marini, a research fellow at Gran Sasso Science Institute and CUOREs Run Coordinator. The resulting sensitivity of the detector is truly phenomenal. When there were large earthquakes in Chile and New Zealand, we actually saw glimpses of it in our detector, said Marini. We can also see waves crashing on the seashore on the Adriatic Sea, 60 kilometers away. That signal gets bigger in the winter, when there are storms.

Despite that phenomenal sensitivity, CUORE hasnt yet seen evidence of neutrinoless double beta decay. Instead, CUORE has established that, on average, this decay happens in a single tellurium atom no more often than once every 22 trillion trillion years. Neutrinoless double beta decay, if observed, will be the rarest process ever observed in nature, with a half-life more than a million billion times longer than the age of the universe, said Danielle Speller, Assistant Professor at Johns Hopkins University and a member of the CUORE Physics Board. CUORE may not be sensitive enough to detect this decay even if it does occur, but its important to check. Sometimes physics yields surprising results, and thats when we learn the most. Even if CUORE doesnt find evidence of neutrinoless double-beta decay, it is paving the way for the next generation of experiments. CUOREs successor, the CUORE Upgrade with Particle Identification (CUPID) is already in the works. CUPID will be over 10 times more sensitive than CUORE, potentially allowing it to glimpse evidence of a Majorana neutrino.

But regardless of anything else, CUORE is a scientific and technological triumph not only for its new bounds on the rate of neutrinoless double beta decay, but also for its demonstration of its cryostat technology. Its the largest refrigerator of its kind in the world, said Paolo Gorla, a staff scientist at LNGS and CUOREs Technical Coordinator. And its been kept at 10 mK continuously for about three years now. Such technology has applications well beyond fundamental particle physics. Specifically, it may find use in quantum computing, where keeping large amounts of machinery cold enough and shielded from environmental radiation to manipulate on a quantum level is one of the major engineering challenges in the field.

Meanwhile, CUORE isnt done yet. Well be operating until 2024, said Bucci. Im excited to see what we find.

Reference: Search for Majorana neutrinos exploiting millikelvin cryogenics with CUORE by The CUORE Collaboration, 6 April 2022, Nature.DOI: 10.1038/s41586-022-04497-4

CUORE is supported by the U.S. Department of Energy, Italys National Institute of Nuclear Physics (Instituto Nazionale di Fisica Nucleare, or INFN), and the National Science Foundation (NSF). CUORE collaboration members include: INFN, University of Bologna, University of Genoa, University of Milano-Bicocca, and Sapienza University in Italy; California Polytechnic State University, San Luis Obispo; Berkeley Lab; Johns Hopkins University; Lawrence Livermore National Laboratory; Massachusetts Institute of Technology; University of California, Berkeley; University of California, Los Angeles; University of South Carolina; Virginia Polytechnic Institute and State University; and Yale University in the US; Saclay Nuclear Research Center (CEA) and the Irne Joliot-Curie Laboratory (CNRS/IN2P3, Paris Saclay University) in France; and Fudan University and Shanghai Jiao Tong University in China.

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Physicists Are Closing In on the Next Breakthrough in Particle Physics And the Search for Our Own Origins - SciTechDaily

Whats going on in the white room is as important as what isnt.

Behind thick walls and a door sealed with a handwheel, the worlds magnetic fields are reduced to essentially nothing. Freed from this background noise, the magnetic fields generated by neurons firing in the brain fields a billion times smaller than Earths can be measured, providing a glimpse into the brains black box.

Inside the room, sitting snug on 17-year-old Keya Shapiros head, is a helmet, dotted with small black rectangles each containing a bit of quantum physics, which helps peer into the inner workings of her brain.

Born with a left side that is weaker than her right, Keya has had to do pediatric constraint-induced movement therapy (PCIMT) for years. For Keya, the therapy involves putting her right arm in a cast and performing physical therapy with her left hand, strengthening it and developing dexterity.

The therapy has worked: the high school senior plays tennis and shoots photos.

But now, Keyas PCIMT experience is going to become a test case for a different way to view whats going on inside the human brain.

Behind thick walls is a hole in the Earths magnetic field.

Gray Matter, Black Box

When it comes to the brain, there is so much we just dont know.

Current methods of imaging the brain all have their drawbacks. They can be too slow to show whats going on, as if watching a View-Master instead of a movie. They can be imprecise, not giving us the finer details of whats going on. And, like MRI, they can require large equipment, unusual clinical settings, and lying unnaturally still for long periods of time.

We cant yet measure the brain how we use it.

Thats what this experiment is supposed to change. The Virginia Tech researchers outside of the sealed box are imaging Keyas brain using a tool that may be a step towards solving those limitations.

Called optically-pumped magnetometers (OPMs), they measure the magnetic fields created by firing neurons which is why Keya is sitting in that hole in the Earths magnetic field, which would normally drown out the neurons tiny signals.

OPMs are faster than other brain imaging devices, and they provide a more accurate picture of where neurons are firing than measuring the brain cells electrical fields.

They can also allow a subject to move while recording their brain activity, getting us one step closer to neurosciences holy grail, measuring the brain out in the wild. (Gotta do something about those blaring magnetic fields out there, though.)

Here at Virginia Techs Fralin Biomedical Research Institute, a team is working to optimize the technology, establishing best practices for using OPM to study social situations.

The OPM and white room technology the researchers are developing will allow them to fulfill their mandate to be the first in the world to study the brain activity underlying social interactions during face-to-face, upright exchanges starting with patients like Keya and their therapists.

Located in the shadows of southwest Virginias Blue Ridge Mountains, the Fralin Biomedical Research Institute at Virginia Tech-Carilion is pioneering new forms of functional brain imaging. Image by the author.

The Brain and the Blue Ridge

Regional jets the kind painted like United but operated by Air Wisconsin bounce on the winds above Roanoke. You look up at the mountains of Virginias Blue Ridge as you land; their jagged green lines hem the horizon.

And in their shadows sits the Fralin Institute.

Keyas been coming to Virginia from her home in Minnesota where she lives with her mom, brother, and mini-Bernedoodle for her PCIMT treatments. She works with senior occupational therapist Mary Rebekah Trucks, in the lab of Stephanie DeLuca, co-director of the Neuromotor Research Clinic.

Now, DeLuca is joining her Virginia Tech colleague Read Montague along with a team at the U.K.s Nottingham University to use OPM to measure the brains of PCIMT patients and their therapists.

DeLuca is hoping that brain measurements can help reveal best practices in the therapy. How important is the constraint on the patients stronger limbs? How much work should the patient do? Are there biomarkers to show the therapy is working?

That data could then be used to optimize PCIMT and help convince more insurance providers to pay for it.

For Montague, the OPM is yet another way to see into the brain.

Harnessing quantum physics, the researchers can read the incredibly minute magnetic fields of neurons firing measuring the brain with speed and precision.

As head of Fralins Center for Human Neuroscience Research, Montague (whos got a hint of Reed Richards about him) and his colleagues have been training AI models to diagnose mental health disorders; using fMRI to better understand and battle addiction; and dropping probes into the brains of patients to take real-time measurements of their neurotransmitters.

The idea is that future patients coming to Roanoke to receive PCIMT with DeLuca and Trucks will have their sessions measured as well therapist and patients inner-most interactions revealed by a quantum effect on atoms.

Eventually, the hope is that the OPM sensors can be placed ever closer to patients heads, allowing for ever more precise measurements and something even closer to measuring the brain in a realistic setting.

Itll take developing into a field for it to really move, Montague says. Not just us here in Appalachia.

Currently, no one else in North America is doing functional neuroimaging exactly like this, Virginia Tech says; theres a similar, smaller facility in Texas, but it is not yet designed for measuring two people at once or allowing for movement.

The Brain at Work

Functional neuroimaging is exactly what it sounds like: taking images of the brain at work. Theres multiple ways to do this, and all have their pros and cons.

Take functional MRIs. An fMRI measures changes in blood flow. By looking at where the blood is flowing in the brain, we can infer what parts of the brain are working harder than usual.

The technique has some notable drawbacks, however; measuring the blood flow, rather than the brain cells, is an indirect measurement of brain activity. fMRIs also take an eternity between each snapshot they have low temporal resolution.

Its like a flipbook of activity compared to a video.

OPMs may be a step closer to neurologys holy grail: measuring the brain in a naturalistic setting.

By comparison, magnetoencephalography (MEG) and electroencephalography (EEG) provide direct measurements of brain activity.

MEGs, a category that includes OPM, sense brain cells magnetic fields, and EEGs measure the electrical currents. And they do so much quicker than the fMRI.

What MEG and EEG look at is the function of the brain, says Elena Boto, a research fellow at the University of Nottinghams Sir Peter Mansfield Imaging Centre.

The brain, we know its an electrical circuit. So to measure the functionality of the brain, you need to look at the currents or magnetic fields associated with these currents that are produced by assemblies of neurons in the brain.

What sets MEG apart from EEG is how accurately it can pinpoint the location of the neurons that are firing.

The magnetic field goes through your skull and water undisturbed, says Svenja Knappe; the electric signals do not, and the end result is a blurred image.

Knappe is an associate research professor at the University of Colorado and co-founder of FieldLine Inc., an OPM-MEG maker. Knappe was part of the team that developed OPMs at the National Institute of Standards and Technology (NIST), and was previously senior scientist at Quspin, which commercialized the OPM and built the ones in use at Virginia Tech.

Most MEG readings are taken using sensors called SQUIDs. These need to be kept frigid via liquid helium to work, so SQUIDs are placed into rigid, Cerebro-like headpieces that hamper movement and keep the sensors precious centimeters away from the brain. Even that tiny distance impacts how well the SQUIDs can measure the brain.

The OPM sensors on Keyas head do not need to be kept ultra-cold. Without the need for liquid helium, they can be deployed much closer to her scalp.

The main benefit of the OPMs from my point of view is that they can be placed on the head closer to the source of interest, says Samu Taulu, director of the I-LABS MEG Brain Imaging Center at the University of Washington.

Because the magnetic fields are so small, even a minute distance between the sensors and the brain reduces accuracy. The infants measured via MEG in Taulus lab provide a better reading than you or I would; their skulls are thinner!

The lack of liquid helium means that the OPM sensors can be free of a rigid helmet, which makes movement easier. According to Taulu, subjects in traditional MEGs can move as well; weve got the math to balance that out when we look at the data. Although, Knappe points out, the rigid helmets are stationary, limiting any movement.

From Atomic Clocks to the Black Box

Each of the OPM sensors are essentially an atomic clock.

They contain rubidium gas sensitive to magnetic fields and their orientation.

Depending on the fluctuations of the magnetic field how cloudy that [gas] is changes, says Fralin Biomedical Research Institute associate professor Stephen LaConte.

By shining a laser through the gas, OPMs use the amount of light transmitted to measure the presence and strength of magnetic fields.

By eliminating the magnetic field of the Earth and other objects within the mag-shielded room and controlling for the ones inside the room, like your heart and muscles you can put together a picture of where neurons are firing in the brain with a speed and accuracy that other neuroimaging techniques lack.

Keya sits and stares, and the magnetic fields generated by her brain are measured. Shes not supposed to actively think, which of course now has her realizing how she thinks.

A Measured Interaction

Inside the white room, Keya stares at a plus sign projected on a screen. Shes wearing a cast extending from her right shoulder out past her fingertips. The device is taking a resting-state reading of her mind; the sensors are warm on her head, almost lulling her to sleep.

The cast is removed, she sits and stares, and the magnetic fields generated by her brain are measured again. Shes not supposed to actively think, which of course now has her realizing how she thinks.

She wonders if Montague and the researchers, watching via webcam from an observation room, can tell she can hear them over the comm system can tell where in her brain she is hearing them.

She taps her fingers, left or right, following guidance on the screen; she does it again, but only in her head.

And the magnetic fields hum secrets to the scientists outside.

Wed love to hear from you! If you have a comment about this article or if you have a tip for a future Freethink story, please email us at tips@freethink.com.

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In a hole in Earths magnetic field, neuroscientists are peering into the human brain - Freethink

Since the steam engine began modernizing the world, the second law of thermodynamics has reigned over physics, chemistry, engineering and biology. Now, an upgrade is underway.

Thermodynamics the study of energy originated during the 1800s, as steam engines drove the Industrial Revolution. To understand its second law, imagine a sponge cake, fresh from the oven, cooling on a countertop. Scent molecules carrying heat drift away from the cake. A physicist might wonder: In how many ways can these molecules be arranged throughout the volume of space they currently occupy? We call this number of arrangements the molecules entropy. If the volume just encloses the cake (as it does when the cake is freshest), the entropy is relatively small. If the volume encompasses the whole kitchen (after the molecules have had time to travel farther), the entropy is exponentially larger. The second law of thermodynamics decrees that the entropy of every closed, isolated system (such as our kitchen, assuming the windows and doors are shut) grows or remains constant. Accordingly, the scent of sponge cake wafts across the entire kitchen and never recedes.

We sum up this behavior in an inequality: $latex S_f ge S_i$,where $latex S_i$is the molecules initial entropy and $latex S_f$ their final entropy. The inequality is useful but vague, because it doesnt tell us how much the entropy will grow, except in a special case: when the molecules are at equilibrium. That happens when large-scale properties such as temperature and volume remain constant, and no net flows of anything such as energy or particles enter or leave the system. (For example, our cakes scent molecules reach equilibrium after theyve fully filled the kitchen.) At equilibrium, the second law strengthens to an equality: $latex S_f = S_i$. This simple, general equality provides precise information about many different types of thermodynamic systems at equilibrium.

But you and I and most of the world are far from equilibrium. And far from equilibrium is the wild west to theoretical physicists and chemists: unpredictable and untidy. Imposing laws on the wild west meaning, for us, proving equalities about physics far from equilibrium is quite difficult.

But its not impossible. For decades, physicists have worked with equalities that strengthen the second law. These equalities are known as fluctuation relations. They connect properties of systems far from equilibrium (which are difficult to reason about theoretically) with equilibrium properties (which are easy to reason about).

To see fluctuation relations in action, imagine a microscopic strand of DNA floating in water. Floating quietly, the DNA is at equilibrium, sharing the waters temperature. Using lasers, we can hold one end of the strand steady and pull the other end. Stretching the strand jolts it out of equilibrium and requires work in the physics sense of the word: structured energy harnessed to accomplish a useful task. The amount of work required fluctuates from one pulling of the strand to the next, since a water molecule sometimes kicks the strand here, sometimes there. That means every possible amount of work has some probability of being needed during the next pull.

It turns out that these probabilities which describe the DNA when its far from equilibrium are directly related to properties that the DNA has at equilibrium. And that relation can be captured by an equality.

This is the core of fluctuation relations: Properties of a system far from equilibrium participate in an equality with equilibrium properties. My colleague Chris Jarzynski at the University of Maryland discovered this in 1997. (Hes so modest, he calls the equality the nonequilibrium fluctuation relation, while the rest of us call it Jarzynskis equality.) Although the DNA experiment provided one of the most famous tests of this principle, the equation governs loads of systems, including those involving electrons, beads the size of bacteria and brass oscillators that resemble centimeter-long tire swings.

Fluctuation relations have implications fundamental and practical. For starters, from these equalities we can derive an expression of the second law of thermodynamics. So fluctuation relations not only extend our knowledge far from equilibrium, as we saw with the DNA strand, but also recapitulate information we know about equilibrium.

But the true power of fluctuation relations lies in an ironic fact: While equilibrium properties are easier to reason about theoretically, they are harder to measure experimentally than far-from-equilibrium properties. For instance, to measure the work needed to stretch the DNA far out of equilibrium, we can simply pull the strand quickly for a short time. In contrast, to measure the work needed to stretch it while it remains at equilibrium, wed have to stretch so slowly that the DNA would always remain practically at rest so our experiment would take an infinitely long time.

Chemists, biologists and pharmacologists are interested in the equilibrium properties of proteins and other molecules, so using fluctuation relations gives them an experimental foothold. They can perform many short nonequilibrium trials and measure the work required in each. From this data, they can infer the probability of needing any given amount of work in the next nonequilibrium trial. Then they can plug those probabilities into the far-from-equilibrium side of the fluctuation relation to determine the equilibrium side. This method still requires oodles of trials, but researchers have leveraged mathematical tools to mitigate the difficulty.

In this way, fluctuation relations have revolutionized thermodynamics, galvanizing experiments and providing detailed predictions about the world far from equilibrium. But their usefulness doesnt stop there.

During the 2000s, quantum thermodynamicists those of us who study how quantum physics changes classical concepts like work, heat and efficiency wanted in on the fun, even though our discipline introduces extra puzzles. How to define and measure quantum work is unclear thanks to quantum uncertainty; for instance, measuring a quantum systems energy changes that energy.

As a result, different researchers have proposed different definitions for quantum work. I imagine the various definitions as species in a Victorian menagerie. The hummingbird definition requires us to measure the quantum system gently, to disturb the energy only a little as the fluttering of a hummingbirds wings by your ear for an instant would disturb you. A wildebeest definition keeps to the middle of the pack, focusing our attention on average energy exchanges. Other definitions flutter, twitter and trumpet across the quantum-thermodynamics literature.

As you might expect, different definitions lead to different quantum fluctuation relations. The same is true for similar definitions adapted to different physical settings. Some relations are easier to test experimentally, while some are abstract and mathematical. Some describe high-energy particles, like those smashed together at CERN; one describes chaos in black holes; and one describes the universes expansion. Experimentalists have tested some quantum fluctuation relations with trapped ions, quantum dots and more.

Will one equality rise to the top of the pile, like a monarch whos bested all their relatives for the throne? I expect not. In my opinion, which definitions and equations are useful depends on which system youre interested in, how you poke it and how you can measure it.

The plurality of quantum fluctuation relations contrasts with the unity stereotypically prized by physicists, such as the long-sought Theory of Everything expected to unify all the fundamental forces. Perhaps some principle will unify the quantum fluctuation relations, revealing them to be different sides of a multidimensional coin. Or perhaps quantum thermodynamics is simply richer than other fields of physics.

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Beyond the Second Law of Thermodynamics - Quanta Magazine

Name:Ehsan Samei

Position:Duke HealthChief Imaging Physicist; Duke University Professor of Radiology, Medical Physics, Biomedical Engineering, Physics, and Electrical and Computer Engineering

Years at Duke:22

What he does at Duke:Whether its an X-ray, a CT scan, an MRI, an ultrasound or a mammogram, medical imaging is at the heart of patient care.Duke's roughly 500 imaging machines see around 700,000 to 800,000 patients per year. In addition to technologists and radiologists, Duke has around a dozen imaging physicists overseeing the use of these machines and ensuring that, across the entire health system, the technology and techniques are creating the most useful and accurate images. As the Chief Imaging Physicist, Dr. Ehsan Samei leads this group.

Samei also spearheads research in medical imaging, seeing how existing technology can be used to see things in new ways. And as the principal investigator of theCenter for Virtual Imaging Trials, which was created in 2021, hes exploring the capabilities of using virtual patients and virtual machines to speed up the development of potential medical breakthroughs.

The crux of the problem, both in the clinical domain and the research domain, is that imaging is an approximation, not reality, said Samei, who received the2022 Marie Sklodowska-Curie Awardfrom the International Organization for Medical Physics. Its never a perfect rendition of reality, but an approximation. So the question Im working on is, how much of an approximation is it, and can we make a better one?

What he loves about Duke:Samei is grateful to have a strong network of colleagues who combine innovative ideas with the collaborative and hard-working spirits needed to push those ideas forward.

What attracted me to Duke is that there are so many brilliant people here, Samei said. I feel that what makes programs and universities worthwhile isnt the project, but the brilliance of the people who actually do the project.

Most memorable day at work:In 2021, Duke became one of the few facilities in the world to acquire a Photon-Counting CT Scanner. For Samei, who had been advocating for Duke to add one, the chance to finally use it tohelp patientswas a thrill. He recalls seeing images with a level of clarity and detail that hed previously been unable to see. And when those images were able to help doctors diagnose patients vexing health problems, it validated the efforts put into bringing the technology to Duke.

You can talk about photon counting and quantum mechanics and all of that stuff, but it only matters when you actually care for the individual and solve their problem, Samei said.

When hes not working, he likes to:Classical music, from such iconic composers as Bach, Schubert and Brahms, is one of Sameis passions. He cherishes opportunities to see live performances, and chances to perform himself. Growing up in Iran, Samei began playing the flute, one of the few instruments small enough to play discreetly in a country where music was banned. More recently, hes enjoyed playing alongside other musicians in semi-professional ensembles.

I used to play a lot more, but now I just dont have the time, Samei said.

Something unique in his workspace:On a shelf inhis office in Hock Plaza, Samei has what looks like a framed record. But a closer look reveals images of bones set within the disc. The item is whats known as abone record.Made in Soviet-era Russia, where western music was strictly banned, these bootleg records often of jazz or early rock n roll were pressed on discarded X-ray slides. A friend gave one to Samei as a gift.

This embodies many of my interests, Samei said. There's medical imaging in there. It has music. And I grew up in Iran during the Islamic revolution when music was banned, so I know that music in itself is an act of resistance.

Lesson learned during the pandemic:Samei gained an appreciation for the periods of time that exist between tasks, meetings and events that define a day. Prior to the pandemic, when offices were full of people and most interactions were in person, these times were when colleagues could chat, or when minds were allowed to wander.

Its amazing how much life happens in the margins, Samei said. On the days when youre going from Zoom meeting to Zoom meeting, those margins are gone and your brain doesnt have a chance to recalibrate.

Something most people dont know about him:Samei is an avid runner and has completed five marathons. One of those was the 2013 Boston Marathon, which was remembered for terrorist attack that claimed three lives near the finish line. Samei had completed the course and left the area roughly 45 minutes before the homemade bombs were detonated.

Thankfully my family decided not to accompany me, Samei said. I was incredibly grateful for that.

Is there a colleague at Duke who has an intriguing job or goes above and beyond to make a difference?Nominate that personfor Blue Devil of the Week.

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Blue Devil of the Week: Making the Invisible Visible through Imaging - Duke Today

Almost 50 years ago, two influential books on Buddhism and physics were published. First came The Dancing Wu Li Masters by Gary Zukav. Fritjof Capras The Tao of Physics followed. Both books were international bestsellers. Both attempted to show how quantum mechanics the physics of molecules, atoms, and subatomic particles recovered the core tenets of Buddhist philosophy.

This weekend, Marcelo and I will attend an amazing meeting called Buddhism, Physics, and Philosophy Redux at the University of California, Berkeley Center for Buddhist Studies. Since the meeting aims to re-examine what, if any, relationship might bind Buddhist perspectives on the nature of reality to those of modern physics, I thought this would be a great time to explain why that goal is meaningful.

I read The Tao of Physics as a student in a freshman physics class in 1981. It blew me away, but more for its excellent descriptions of quantum mechanics than for its argument that Buddhism and physics overlap. Even then, I felt the argument stretched itself too thin. As the years progressed, I got my PhD in theoretical physics and began practicing Zen Buddhism seriously. I developed a much better perspective on what Zukav and Capra were arguing for, and I bought their arguments even less.

The real problem with both books is all about interpretation; specifically, quantum interpretation. From its very start in the early 20th century, quantum mechanics was known to be weird. Classical physics builds a complete picture of the world from tiny particles bouncing off each other like nano billiard balls. Quantum mechanics, on the other hand, allows for no easy visualization.

Instead, quantum mechanics tells us that particles like atoms can be in two places at the same time until a measurement is made. It tells us that the properties of those atoms can be inherently uncertain, as if they were actually smeared out and did not have definite values. It also tells us that particles on opposite sides of the Universe can be entangled such that what happens to one instantly affects the other, even though no physical signal had time to pass between them.

For the last 100 years, physicists have scratched their heads over this basket of quantum weirdness. And over those same 100 years, they have developed different interpretations of the theory. Each interpretation paints a different picture of what is meant by an atom in terms of physical reality. In the same way, each paints a different picture of what is meant by a measurement as an interaction between something that is observed, and something else that is the observer.

The thing is, there are many of these interpretations. One of these is called the Copenhagen Interpretation. It is named after the city where Neils Bohr, one of the founders of quantum mechanics, lived.

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The interpretation does seem to have some interesting parallels with the classical philosophies that emerged from India and Asia when Buddhism was the dominant religion. In particular, the Copenhagen Interpretation seems to open a path for observers to play a strange but central role in grounding what can happen in a quantum experiment. Thus, the idea that the observer affects the observed is certainly something the Copenhagen Interpretation might seem to allow for, and this might be connected with certain tenets of Buddhism. Now, there are couple of mights in that last sentence. You can find physicists who are pro-Copenhagen Interpretation just as you can find Buddhist scholars who would disagree with it. But that was not the main problem with Capra and Zukovs thesis.

The real problem with the 1970s version of Quantum Buddhism was that it privileged the Copenhagen Interpretation. It never really addressed the fact that Copenhagen was just that an interpretation with no more validity than other interpretations (such as the Many Worlds view favored by folks like Sean Carroll). As time went on and Quantum Buddhism became a staple of New Age wackiness, that key point the Copenhagen Interpretation is just one interpretation was completely forgotten.

Fifty years later, it is now time to re-examine Buddhist philosophical perspectives and the frontiers of physics. The point is not to show that physics is confirming the truths of Buddhism. That will never happen, nor should it. Instead, once we recognize that physics has always been influenced by philosophical ideas, we can recognize that throughout its entire history those ideas have come solely from Western philosophers. But half a world away, Buddhist philosophers were encountering many similar questions, like the nature of time and causality, or how consciousness stands in relation to the world.

Because they were coming from a different history, these Buddhists explored other kinds of responses to the same questions their Western counterparts pondered. In this way, there may be perspectives in the long history of Buddhist philosophy that prove fruitful for physicists pushing at their own frontiers the places where we are stuck, or hitting paradoxes. That is why I am so very excited for what is going to happen over the next few days.

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What does Buddhism offer physics? - Big Think