Daily Archives: December 12, 2020

According to the many-worlds interpretation of quantum mechanics, the universe is constantly dividing and taking you with it so would you recognise your other selves if you met them?

By Daniel Cossins

Jonathan Knowles/Getty Images

BIOLOGICALLY speaking, there is definitively only one you (see How likely are you?). Physics might give you pause for thought, however. The most bewildering argument against your uniqueness comes from quantum mechanics, the fundamental theory that describes the often counter-intuitive behaviour of subatomic particles. It might imply not only that there are multiple, identical versions of you, but even that there are an infinite number of yous out there.

The quantum realm is notoriously fuzzy: quantum objects such as particles are described in terms of probabilities, encoded in mathematical widgets called wave functions that give you the odds on any number of different states the object might be in. Only when you observe or measure it does the object take on one of those states, at least from your perspective.

Quantum theory might imply there are an infinite number of yous out there

The truth of what happens at this point and indeed what, if anything, the wave function itself is trying to tell us about reality divides physicists. Many stick with a cop-out known as the Copenhagen interpretation: essentially, that we can never know what is happening in this fuzzy pre-measurement realm. In other words, quantum theory makes predictions about reality, but says nothing about what goes on under the hood.

That isnt good enough for some. Physicists who subscribe to the rival many worlds interpretation insist that all the possibilities encoded in the wave function are real, and that they continue to exist in different universes that split off from ours every time a quantum

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If the multiverse exists, are there infinite copies of me? - New Scientist

CHICAGO: Out of Mesopotamia, by Salar Abdoh, journeys through a labyrinth of life, from warzones to non-warzones. Abdohs profound novel follows a middle-aged man named Saleh, an Iranian journalist who has embedded himself on the frontlines of the wars in Syria and Iraq against Daesh. Taking every opportunity to escape from life in Tehran where he writes for the art section of a newspaper and avoids his state handler and most of the people in his life, Saleh finds himself teetering between life and death as he witnesses the atrocities of combat and befriends men who live to die.

Readers first meet Saleh in Syria where evil lurks around every corner of the war. Traveling with squadrons of soldiers, some of whom he can call friends, Saleh attempts to understand the war, or the chaos of it, where death is but a moment and ever-rolling replacements for soldiers are always near. He is surrounded by men who are protecting their holy sites, preserving the land of their forefathers, and by those who only wish to become martyrs. To them, the fight is their duty and because of their lack of options, they leave behind their families in the hope that they will bring prestige to their name when they are gone. The fighters are vultures perched on Mesopotamias tired bones.

Abdoh weaves Salehs story and the war seamlessly, the juxtaposition of writing about war and actually fighting in it forces predicaments on Salehs life. How can he go back to living life when he has witnessed men who live to die? He is living and writing history simultaneously as it happens and losing himself while doing so. He distances himself from life when death is always so close. And he struggles with his own career in the media, where these men who live to fight and die are the ones that bring him and his colleagues the most prestige.

With first-hand experience with militias in Iraq and Syria, Abdoh travels between war and peace in his novel, picking up on the in-between moments, the ones that are not glorified and where suffering is silent. He insightfully encompasses wars surroundings, the stories that deal with the consequences of war and patriarchal society, where fighters and survivors, much like the art Saleh writes about, lose and gain value with life and death. Where courage is not sought after but mimicked. Through his restless main character, Abdoh explores life and its moments, the value of those moments, and their ever-quiet passing.

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What We Are Reading Today: Understanding Quantum Mechanics by Roland Omnes - Arab News

Dr. Margareth Arst, an early pioneer for women in science, earned her physics Ph.D. in 1947.

It is well-documented that women are underrepresented in STEM, particularly in physics and quantum, although thankfully it is to a lesser degree today than it was many years ago. In the 1930s and 1940s, some people believed that women didn't have the proper brain structure for scientific investigation. Those opinions and other gender prejudices must have made it difficult for a little-known scientist named Margareth Arst to obtain her doctorate in physics in 1947 at the University of Vienna in Austria. According to NSF data, Dr. Arst was one of about twenty women who earned a Ph.D. in physics that year.

Women are not only underrepresented, they are also notably under-recognized for their achievementsparticularly when it comes to the Nobel prize in physics. In 2018, Donna Strickland was awarded a Nobel prize in physics. She was the first woman to receive the award in 55 years. Since 1901, only two other women have won the Nobel physics award. Marie Curie won it (with her husband) in 1903 for the study of spontaneous radiation. Maria Goeppert won it in 1963 for her shell model of the atomic nucleus.

This chart represents the disparity % between men and women across STEM disciplines.

Compared to men, women are underrepresented at all stages of their careers (bachelor's, doctorate, postdoc, and professor) across nearly every STEM discipline. As shown in the above chart, women are only above parity at the bachelor's and doctorate levels for biological sciences, but below parity at more advanced levels.

Even though women are making progress, the fundamental issue causing the imbalance remains. The American Physical Society conducted a survey in 2019 that revealed physics is the most male-dominated of all STEM fields.One thing is for sure, in 1947, there were no support groups or formal mentor programs to encourage female scientists like Dr. Arst to pursue their intellectual passions. It was a matter of self-determination and personal courage if a woman wanted a Ph.D. at that time.

After she obtained her Ph.D. in 1947, Dr. Arst would have been surprised to learn that 70 years in the future, she would serve as the inspiration for her yet unborn daughter to start a support group for women working in the highly technical field of quantum information technology.

Today, at the age of 96, Dr. Arst is still a role model for her daughter, Denise Ruffner, the founder of Women in Quantum (WIQ).Ruffner previously worked for IBM Quantum, Cambridge Quantum Computing, and she is currently employed by IonQ." I think my comfort of being a woman in science and working in a man's world comes from the fact that my mother was my role model," Ruffner said. "She's 96, and for Christmas, I give her physics textbooks, and she loves it. She's still a complete nerd, and it's really cute."

There were additional reasons Ruffner founded Women in Quantum. She felt that women needed a vehicle to highlight their contributions in quantum. She also wanted to give women access to resources that would amplify their voices in the quantum community. WIQ also offers opportunities to collaborate and have fun with fellow female quantum academics, students, entrepreneurs, investors and government representatives.

I asked Ruffner what first gave her the idea for WIQ. She told me two occurrences made her realize that a group like Women in Quantum was necessary. "I was attending an IBM event several years ago and realized I was the only woman there. IBM believes diversity is important, so afterward, it gave me a mission to actively recruit more women. Later, I also noticed that leadership photos on many company websites were only men. That bothered me, so I decided to do something about it."

Ruffner also sought the advice of her friend, Andr Knig, founder of OneQuantum, the parent organization of WIQ, who said, "I believe that it is vital to democratize Quantum Tech and make it accessible to anyone - no matter their age, gender, ethnicity, education or otherwise."

There are several other support groups for women scientists besides WIQ. For example, IBM sponsors a group called the Watson Women's Network, a community of technical staff, primarily based at the T.J. Watson Research Center. The group encourages a workplace environment that advances the professional effectiveness, individual growth, recognition and advancement of all women at IBM Research. The WWN also partners with senior management, human resources, and other diversity network groups to promote mentoring, networking, diversity, knowledge-sharing and recruiting.

Details of the upcoming Women in Quantum Summit III

The Women in Quantum Summit III is a virtual event scheduled for December 14-16.You can register for free here.

Women in Quantum is a chapter of OneQuantum, an organization focused on promoting quantum research and the quantum ecosystem and dedicated to helping quantum gain acceptance and importance in the scientific and business communities. Its important to point out that men are also welcome to join the organization or register for Summit III.

Honeywell Inc., a multinational conglomerate and developer of quantum computing hardware, is the sponsor for the OneQuantum chapter of Women in Quantum. IonQ, also a major developer of quantum computing hardware, is the sponsor for the upcoming Women in Quantum Summit III, along with Women in Technology International (WITI) as a co-sponsor.

WIQ Summit III features high profile women speakers, including founders of prominent quantum technology companies, government representatives, investors and leading academics working in various fields of quantum information science. Summit III will end each day with a virtual cocktail hour to connect attendees with each other on a one-on-one basis for discussion and relationship building.

Ruffner said the cocktail hour allows you to meet people you wouldn't otherwise get to know and it provides a way to expand your network. "It's also fun because you are randomly matched with people. Your bio comes up with your picture and their bio also pops up and you talk to each other for five minutes. After that, you are sent to a queue where you are matched to someone else."

Summit III will also feature Anisha Musti, a 15-year-old New York City high school student. Anisha Musti is the CEO and founder of a quantum company called Q-munity. Her company is a 501c3 nonprofit striving to connect and teach young people about quantum computing.

The Summit III keynote speakers are:

Denise Ruffner provides more information about the upcoming Women in Quantum Summit III in a discussion with Patrick Moorhead and me on the Moor Insights & Strategy YouTube Channelyou can find the link here if interested.

Disclosure:My firm, Moor Insights & Strategy, like all research and analyst firms, provides or has provided research, analysis, advising, and/or consulting to many high-tech companies in the industry, including IBM and Honeywell. I do not hold any equity positions with any companies cited in this column.

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The Upcoming Women In Quantum Summit III And Its Secret 70 Year-Old Legacy - Forbes

The case for quantum mechanics operating at the macro level is growing.

Observable in human behaviour, societal trends and global phenomena, a quantum perspective allows new insights into international relations, world politics and global systems.

But it also poses a fundamental challenge to what we know about ourselves and the world around us.

With the support of the Carnegie Corporation of New York, Project Q continues to bring the leading thinkers and practitioners together to grapple with these ideas and shape the path forward.

Project Q's 'Quantizing International Relations', a special issue of Security Dialogue edited by James Der Derian and Alexander Wendt, is available online now.

Project Q is an initiative of the Centre for International Security Studies, led by Professor James Der Derian. An expanded collected volume of essays, to be published by the Oxford University Press, and a feature-length documentary film, Project Q: War, Peace and Quantum Mechanics, will appear in 2021.

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International Relations goes quantum - News - The University of Sydney

It's not often we pause in the middle of our day and think about the nature of viscosity, unless perhaps we're on our way to Oil Can Henry's for an oil change onthe 'ol family truckster. But thanks to some fluid-friendly physicists, now we've got a reason!

According to Princeton University's official definition, "Viscosityis a measure of a fluid's resistance to flow.It describes the internal friction of a moving fluid. A fluid with large viscosity resists motion because its molecular makeup gives it a lot of internal friction." Got that?

Now that we're all in agreement as to what constitutes resistant flow, imagine a free-moving substance, call it a "perfect fluid" that operates with the least possible amount of friction allowed by the immutable laws of quantum mechanics, and you'll grasp what scientists at MIT have just created. Far from just a friction-less environment, the results of the experiments might aid physicistsin theirpursuits to investigatethe viscosity in cores of neutron stars, the plasma of the ancientuniverse, and additional forcefulinteracting fluids.

To create this universal magic, scientists made a recording of sound waves delivered through a controlled gas of basic particles called fermions. This rising scale, known as a glissando, can be heard in the clip below, which demonstrates the distinct frequencies that the gas resonates like a guitar string when sound waves are injected.

By analyzingthousands of sound waves shootingthrough this gas to calculateits sound diffusion, or how fastsound dissipates, the team was able to determine thematerials viscosity, or internal friction. Theresults of their effortswere published this week in the online journal, Science.

Its quite difficult to listen to a neutron star, says study co-author Martin Zwierlein, the Thomas A. Frank Professor of Physics at MIT. But now you could mimic it in a lab using atoms, shake that atomic soup and listen to it, and know how a neutron star would sound.The stars resonant frequencies would be similar to those of the gas, and even audible if you could get your ear close without being ripped apart by gravity.

So low was the value of the sound diffusion that it could only be measuredby a molecular-level of friction. Itconfirmed that thisstrongly interacting fermion gas demonstrates propertiesofa perfect fluid, and is considered universal in nature. This marks the first instance ofscientistsmeasuringsound diffusion in a perfect fluid.

Fermions are elementary particles likeelectrons, protons, and neutrons, and areregarded asthe building blocks of all matter.Normally content to exist as loners, fermions display characteristics of low viscosity when aroused and made to strongly interact.To manufacture this unflawedfluid, the researchers employeda system of lasers to entrap a gas of lithium-6 atoms, which are recognized asfermions.

By configuringlasers to form an optical box around the fermion gas, scientists were able to tune them to causefermions to ricochet back into the box when they collided with the edges of the optical enclosure.

All these snapshots together give us a sonogram, and its a bit like whats done when taking an ultrasound at the doctors office, Zwierlein added. The quality of the resonances tells me about the fluids viscosity, or sound diffusivity. If a fluid has low viscosity, it can build up a very strong sound wave and be very loud, if hit at just the right frequency. If its a very viscous fluid, then it doesnt have any good resonances.

Zwierlein and his colleagues are confident that thesenew tools can be harnessed toestimate quantum friction withincosmicmatter likeneutron stars, and also allowfor a greaterunderstanding of howdiversematerials can be manipulatedto portrayperfect, superconducting flow.

This work connects directly to resistance in materials, Zwierlein notes. Having figured out whats the lowest resistance you could have from a gas tells us what can happen with electrons in materials, and how one might make materials where electrons could flow in a perfect way. Thats exciting.

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Scientists just engineered the perfect friction-less fluid and here's what it sounds like! - SYFY WIRE

Scientists have captured the sound of a perfect fluid, which flows with the smallest amount of friction allowed by the laws of quantum mechanics. Credit: Christine Daniloff, MIT

The results should help scientists study the viscosity in neutron stars, the plasma of the early universe, and other strongly interacting fluids.

For some, the sound of a perfect flow might be the gentle lapping of a forest brook or perhaps the tinkling of water poured from a pitcher. For physicists, a perfect flow is more specific, referring to a fluid that flows with the smallest amount of friction, or viscosity, allowed by the laws of quantum mechanics. Such perfectly fluid behavior is rare in nature, but it is thought to occur in the cores of neutron stars and in the soupy plasma of the early universe.

Now MIT physicists have created a perfect fluid in the laboratory, and found that it sounds something like this:

This recording is a product of a glissando of sound waves that the team sent through a carefully controlled gas of elementary particles known as fermions. The pitches that can be heard are the particular frequencies at which the gas resonates like a plucked string.

The researchers analyzed thousands of sound waves traveling through this gas, to measure its sound diffusion, or how quickly sound dissipates in the gas, which is related directly to a materials viscosity, or internal friction.

Surprisingly, they found that the fluids sound diffusion was so low as to be described by a quantum amount of friction, given by a constant of nature known as Plancks constant, and the mass of the individual fermions in the fluid.

This fundamental value confirmed that the strongly interacting fermion gas behaves as a perfect fluid, and is universal in nature. The results, published today in the journal Science, demonstrate the first time that scientists have been able to measure sound diffusion in a perfect fluid.

Scientists can now use the fluid as a model of other, more complicated perfect flows, to estimate the viscosity of the plasma in the early universe, as well as the quantum friction within neutron stars properties that would otherwise be impossible to calculate. Scientists might even be able to approximately predict the sounds they make.

Its quite difficult to listen to a neutron star, says Martin Zwierlein, the Thomas A. Frank Professor of Physics at MIT. But now you could mimic it in a lab using atoms, shake that atomic soup and listen to it, and know how a neutron star would sound.

While a neutron star and the teams gas differ widely in terms of their size and the speed at which sound travels through, from some rough calculations Zwierlein estimates that the stars resonant frequencies would be similar to those of the gas, and even audible if you could get your ear close without being ripped apart by gravity, he adds.

Zwierleins co-authors are lead author Parth Patel, Zhenjie Yan, Biswaroop Mukherjee, Richard Fletcher, and Julian Struck of the MIT-Harvard Center for Ultracold Atoms.

To create a perfect fluid in the lab, Zwierleins team generated a gas of strongly interacting fermions elementary particles, such as electrons, protons, and neutrons, that are considered the building blocks of all matter. A fermion is defined by its half-integer spin, a property that prevents one fermion from assuming the same spin as another nearby fermion. This exclusive nature is what enables the diversity of atomic structures found in the periodic table of elements.

If electrons were not fermions, but happy to be in the same state, hydrogen, helium, and all atoms, and we ourselves, would look the same, like some terrible, boring soup, Zwierlein says.

Fermions naturally prefer to keep apart from each other. But when they are made to strongly interact, they can behave as a perfect fluid, with very low viscosity. To create such a perfect fluid, the researchers first used a system of lasers to trap a gas of lithium-6 atoms, which are considered fermions.

The researchers precisely configured the lasers to form an optical box around the fermion gas. The lasers were tuned such that whenever the fermions hit the edges of the box they bounced back into the gas. Also, the interactions between fermions were controlled to be as strong as allowed by quantum mechanics, so that inside the box, fermions had to collide with each other at every encounter. This made the fermions turn into a perfect fluid.

We had to make a fluid with uniform density, and only then could we tap on one side, listen to the other side, and learn from it, Zwierlein says. It was actually quite diffult to get to this place where we could use sound in this seemingly natural way.

The team then sent sound waves through one side of the optical box by simply varying the brightness of one of the walls, to generate sound-like vibrations through the fluid at particular frequencies. They recorded thousands of snapshots of the fluid as each sound wave rippled through.

All these snapshots together give us a sonogram, and its a bit like whats done when taking an ultrasound at the doctors office, Zwierlein says.

In the end, they were able to watch the fluids density ripple in response to each type of sound wave. They then looked for the sound frequencies that generated a resonance, or an amplified sound in the fluid, similar to singing at a wine glass and finding the frequency at which it shatters.

The quality of the resonances tells me about the fluids viscosity, or sound diffusivity, Zwierlein explains. If a fluid has low viscosity, it can build up a very strong sound wave and be very loud, if hit at just the right frequency. If its a very viscous fluid, then it doesnt have any good resonances.

From their data, the researchers observed clear resonances through the fluid, particularly at low frequencies. From the distribution of these resonances, they calculated the fluids sound diffusion. This value, they found, could also be calculated very simply via Plancks constant and the mass of the average fermion in the gas.

This told the researchers that the gas was a perfect fluid, and fundamental in nature: Its sound diffusion, and therefore its viscosity, was at the lowest possible limit set by quantum mechanics.

Zwierlein says in addition to using the results to estimate quantum friction in more exotic matter, such as neutron stars, the results can be helpful in understanding how certain materials might be made to exhibit perfect, superconducting flow.

This work connects directly to resistance in materials, Zwierlein says. Having figured out whats the lowest resistance you could have from a gas tells us what can happen with electrons in materials, and how one might make materials where electrons could flow in a perfect way. Thats exciting.

Reference: Universal sound diffusion in a strongly interacting Fermi gas by Parth B. Patel, Zhenjie Yan, Biswaroop Mukherjee, Richard J. Fletcher, Julian Struck and Martin W. Zwierlein, 4 December 2020, Science.DOI: 10.1126/science.aaz5756

This research was supported, in part, by the National Science Foundation and the NSF Center for Ultracold Atoms, the Air Force Office of Scientific Research, the Office of Naval Research, and the David and Lucile Packard Foundation.

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MIT Physicists Created a Perfect Fluid and Captured the Sound Listen Here - SciTechDaily

Image Credit:agsandrew/Shutterstock.com

Using quantum physics, researchers are on the cusp of creating sensors that will see further, deeper, and around corners.

Since its inception at the start of the 20th Century, quantum physics has changed how we see the microscopic world. Thanks to advances in sensor technology, this revolutionary and counter-intuitive branch of physics could change our view of the everyday world.

Quantum sensors could be employed in medical scanners, self-driving vehicles, weather pattern assessments, and seismic activity analysis. Therefore, our understanding of the sometimes strange subatomic world is poised to change our everyday lives forever.

Such sensors manipulate aspects of quantum mechanics such as entanglementthe idea that a particle change can instantly influence its entangled partner despite the distance between themand the energy levels that electrons can occupy in atoms to assess the environment around them in devastatingly imaginative ways.

Beneath the surface of urban areas is a mass of utility infrastructures such as pipes, cables and sewers, transport utilities, and even mine shafts, old foundations, and sinkholes.

Public work in these areas is not just delayed and made more expensive by these buried obstacles, they can often pose a legitimate danger to workers and the general public. There are sensors that can probe beneath the ground without penetration. However, technology such as Ground Penetrating Radars (GPR) can only probe a few centimeters beneath the surface before its signal is stifled and pipes and cables can be meters deep.

One possible alternative comes from the quantum realm.

Quantum technology could create a gravity sensor which can detect much deeper beneath the surface. Theoretically, such a sensor could probe to the center of the Earth. Quantum gravity sensors are more useful as they do not send a signal through the ground. Instead, they measure density variations by using a facet of quantum physics known as superposition.

Superposition arises from particles' wave-like behavior and means that a quantum system can technically exist in two contradictory states at once. This contradictory existence continues until measurements are made.

A quantum gravity sensor would drop a cloud of supercooled atoms in a superposition of two different states into an area to be probed. Changes in the atomic cloud and how it passes through the ground are then observed, giving density measurements to the operators above the surface. These changes in density indicate buried obstacles such as pipes and cables, and voids caused by tunnels.

The application of such a system goes way beyond assisting in road works. A quantum gravity sensor could be used in volcanic activity areas to monitor lava flow and help geologists uncover water and mineral deposits. Self-piloted ships could also use the system to navigate and probe the depths of the ocean.

In the UK, the University of Birmingham has teamed with engineering services firm RSK on Gravity Pioneer a project that aims to make quantum gravity sensors a reality.

Self-navigation is a major problem for the car industry. The Insurance Institute for Highway Safety recently produced a report concluding that only one-third of crashes would be avoided by autonomous cars despite being impervious to human error, distraction or driver incapacitation.

The tendency of light to refract off walls and other surfaces can be used to build 3D images, as long as the sensors used to detect light are sensitive enough.This rebounded light could allow self-driving cars to see around corners. More sensitive sensors could also allow these vehicles to see through fog and smoke.

Improving the sensitivity of quantum sensors is one of the primary goals of scientists at the Pritzker School of Molecular Engineering (PME) at the University of Chicago.

The team believes that using a physics phenomenon called non-Hermitian dynamics can prevent a string of photonic cavities that prevent light from leaking from sensors. This results in an improvement in sensitivity without expending extra energy or vastly increasing the photon collection area of sensors.

Video Credit: University of Birmingham/YouTube.com

While quantum computers and even a quantum internet could be on the horizon, these improved information networks will rely heavily on accurate synchronized time-keeping. All the innovations discussed above will also hinge on hyper-accurate clocks over a geographically distributed network.

This precision timing is currently achieved using atomic clocks, which keep time with quantum phenomena and the randomness that lies at the heart of this field of physics. As such, they were probably the first piece of quantum tech to become widely available and probably warrant a mention in any discussion about such advance.

In addition to this, atomic clocks form the foundation of the Global Positioning Systems (GPS) technology that our satnavs and mobile phones rely on every day.

Atomic clocks combine a quartz crystal oscillator with an ensemble of atoms to achieve greater stability. To give you an idea of how accurate this makes them in comparison to a wristwatch that uses a quartz crystal oscillator alone, NASAs Deep Space Atomic Clock will be off by less than a nanosecond after four days and less than a microsecondone-millionth of a secondafter 10 years. This is equal to around one second every 10 million years.

Atomic clocks operate because electrons can only occupy certain energy levels while orbiting an atomic nucleus. They step from one level to another by absorbing or emitting a photon of specific energy.

Atomic clocks have incredible accuracy as photons come in precise packets of energy and it takes an exact amount of energy to make an electron step up.

However, that does not mean atomic clocks cannot be improved. NASA-funded researchers are attempting to use entanglement to create the most precise clock known to man.Entangling atoms in an atomic clock with enough atoms could produce an atomic clock so stable that it would lose a second about once every 30 billion years.

At the moment, these applicationsbarring atomic clocksare strictly in development phases, with some modalities further along than others. But the phenomena that inform these techniques are well established, and it is a matter of time before quantum sensors are market-ready.

In a recent Scientific American article, it was estimated that such sensors could be available in around 35 years.

To get a sense of how important quantum sensors are for the future, the University of Birmingham is leading an 80 million consortium, the UK Quantum Technology Hub for Sensors and Metrology, using quantum effects to build next-generation sensors for gravity, magnetic fields, rotation, time, THz radiation and quantum light.

Professor Kai Bongs, Director of Innovation at the College of Engineering and Physical Sciences at the University of Birmingham, is the consortium's principal investigator. He and his team have identified a market potential for quantum sensors of 4 billion per year, with the possibility of improving the UKs Gross Domestic Product by 10%.

Elsewhere in the UK, the government and private sector has invested 315 million into the second phase of its National Quantum Computing Program (20192024).

It is ironic perhaps that quantum physicsthe science of the very small, could, via quantum sensors, improve our lives in a very big way.

C Freier, M Hauth, V Schkolnik, B Leykauf, M Schilling, H Wziontek, H-G Scherneck, J Muller, and A Peters, (2020), Mobile quantum gravity sensor with unprecedented stability, Journal of Physics: Conference Series, doi:10.1088/17426596/723/1/012050

Young. J, (2020), Self-driving vehicles could struggle to eliminate most crashes, Insurance Institute for Highway Safety, https://www.iihs.org/news/detail/self-driving-vehicles-could-struggle-to-eliminate-most-crashes

McDonald. A., Clerk. A. A., (2020), Exponentially-enhanced quantum sensing with non-Hermitian lattice dynamics, Nature Communications, https://doi.org/10.1038/s41467-020-19090-4

What is an Atomic Clock? NASA JPL, https://www.nasa.gov/feature/jpl/what-is-an-atomic-clock

Are quantum sensors the key to transforming our lives? (2020), The University of Birmingham, https://www.birmingham.ac.uk/research/quest/emerging-frontiers/quantum-sensors.aspx

Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.

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How Could Quantum Sensing Transform Industries and our Society? - AZoSensors

The Big Bang theory says that our universe began with a colossal explosion, about 14 billion years ago, and has been expanding and cooling ever since. Astronomers combine mathematical models with observations to develop workable theories of how the universe came to be, including Albert Einsteins general theory of relativity along with standard theories of fundamental particles. Today, NASA spacecraft such as the Hubble Space Telescope continue measuring the expansion of the universe.We can now tell an unbroken story, from inflation to the postinflation period, to the Big Bang and beyond, says David Kaiser, the Germeshausen Professor of the History of Science and professor of physics at MIT, about the postinflation reheating period that set up the conditions for the Big Bang, and in some sense puts the bang in the Big Bang. Its this bridge period where all hell breaks loose and matter behaves in anything but a simple way. We can trace a continuous set of processes, all with known physics, to say this is one plausible way in which the universe came to look the way we see it today.

Cosmic Inflation Lasted Less than a Trillionth of a Second

Just before the Big Bang launched the universe onto its ever-expanding course, physicists believe, there was another, more explosive phase of the early universe at play: cosmic inflation, which lasted less than a trillionth of a second. During this period, matter a cold, homogeneous goop inflated exponentially quickly before processes of the Big Bang took over to more slowly expand and diversify the infant universe.

The Big Bang Vanishes Scientists Doubt Most Famous Scientific Theory Since Einsteins Relativity

Recent observations have independently supported theories for both the Big Bang and cosmic inflation. But the two processes are so radically different from each other that scientists have struggled to conceive of how one followed the other.

All Hell Breaks Loose Bridging Cosmic Inflation with the Big Bang

Now physicists at MIT, Kenyon College, and elsewhere have simulated in detail an intermediary phase of the early universe that may have bridged cosmic inflation with the Big Bang, reports MIT. This phase, known as reheating, occurred at the end of cosmic inflation and involved processes that wrestled inflations cold, uniform matter into the ultrahot, complex soup that was in place at the start of the Big Bang.

The Extreme Energy that Drove Inflation

Kaiser and his colleagues simulated in detail how multiple forms of matter would have interacted during this chaotic period at the end of inflation. Their simulations show that the extreme energy that drove inflation could have been redistributed just as quickly, within an even smaller fraction of a second, and in a way that produced conditions that would have been required for the start of the Big Bang.

Quantum Effects Deviate from Theory of General Relativity

The team found this extreme transformation would have been even faster and more efficient if quantum effects modified the way that matter responded to gravity at very high energies, deviating from the way Einsteins theory of general relativity predicts matter and gravity should interact.

Alan Guths Theory Small Speck of Matter About a Hundred-Billionth the Size of a Proton

MIT theoretical physicist and cosmologist Alan Guth, who pioneered the theory that the universe dramatically expanded in size in a fleeting fraction of a second after the Big Bang famously said the Big Bang theory says nothing about what banged, why it banged, or what happened before it banged.

The theory of cosmic inflation, first proposed in the 1980s by Guth, the V.F. Weisskopf Professor of Physics, predicts that the universe began as an extremely small speck of matter, possibly about a hundred-billionth the size of a proton. This speck was filled with ultra-high-energy matter, so energetic that the pressures within generated a repulsive gravitational force the driving force behind inflation. Like a spark to a fuse, this gravitational force exploded the infant universe outward, at an ever-faster rate, inflating it to nearly an octillion times its original size (thats the number 1 followed by 26 zeroes), in less than a trillionth of a second.

Powering the Universe? Relic Light of the Big Bang Reveals an Exotic Unknown Force

Like a Spark to a Fuse

Like a spark to a fuse, this gravitational force exploded the infant universe outward, at an ever-faster rate, inflating it to nearly an octillion times its original size (thats the number 1 followed by 26 zeroes), in less than a trillionth of a second.

Kaiser and his colleagues attempted to work out what the earliest phases of reheating that bridge interval at the end of cosmic inflation and just before the Big Bang might have looked like.

The earliest phases of reheating should be marked by resonances. One form of high-energy matter dominates, and its shaking back and forth in sync with itself across large expanses of space, leading to explosive production of new particles, Kaiser says. That behavior wont last forever, and once it starts transferring energy to a second form of matter, its own swings will get more choppy and uneven across space. We wanted to measure how long it would take for that resonant effect to break up, and for the produced particles to scatter off each other and come to some sort of thermal equilibrium, reminiscent of Big Bang conditions.

The teams computer simulations, says MIT, represent a large lattice onto which they mapped multiple forms of matter and tracked how their energy and distribution changed in space and over time as the scientists varied certain conditions. The simulations initial conditions were based on a particular inflationary model a set of predictions for how the early universes distribution of matter may have behaved during cosmic inflation.

The scientists chose this particular model of inflation over others because its predictions closely match high-precision measurements of the cosmic microwave background a remnant glow of radiation emitted just 380,000 years after the Big Bang, which is thought to contain traces of the inflationary period.

A Slight Tweak Quantum Mechanics

The simulation tracked the behavior of two types of matter that may have been dominant during inflation, very similar to a type of particle, the Higgs boson, that was recently observed in other experiments.

Before running their simulations, the team added a slight tweak to the models description of gravity. While ordinary matter that we see today responds to gravity just as Einstein predicted in his theory of general relativity, matter at much higher energies, such as whats thought to have existed during cosmic inflation, should behave slightly differently, interacting with gravity in ways that are modified by quantum mechanics, or interactions at the atomic scale.

In Einsteins theory of general relativity, the strength of gravity is represented as a constant, with what physicists refer to as a minimal coupling, meaning that, no matter the energy of a particular particle, it will respond to gravitational effects with a strength set by a universal constant.

However, at the very high energies that are predicted in cosmic inflation, matter interacts with gravity in a slightly more complicated way. Quantum-mechanical effects predict that the strength of gravity can vary in space and time when interacting with ultra-high-energy matter a phenomenon known as nonminimal coupling.

Kaiser and his colleagues incorporated a nonminimal coupling term to their inflationary model and observed how the distribution of matter and energy changed as they turned this quantum effect up or down.

A Faster Transition

In the end they found that the stronger the quantum-modified gravitational effect was in affecting matter, the faster the universe transitioned from the cold, homogeneous matter in inflation to the much hotter, diverse forms of matter that are characteristic of the Big Bang.

By tuning this quantum effect, they could make this crucial transition take place over 2 to 3 e-folds, referring to the amount of time it takes for the universe to (roughly) triple in size. In this case, they managed to simulate the reheating phase within the time it takes for the universe to triple in size two to three times. By comparison, inflation itself took place over about 60 e-folds.

Reheating was an insane time, when everything went haywire, Kaiser says. We show that matter was interacting so strongly at that time that it could relax correspondingly quickly as well, beautifully setting the stage for the Big Bang. We didnt know that to be the case, but thats whats emerging from these simulations, all with known physics. Thats whats exciting for us.

Guth, the original architect for the theory of cosmic inflation, sees the groups results as an important new development in the study of inflationary models.

While versions of inflation based on a single form of matter give a remarkably good fit to observations, Dave and his collaborators have for a number of years been studying well-motivated models that involve multiple forms of matter also giving an excellent fit to the data, Guth says. Until now, however, the work has been limited to studying the early stages of the ending of inflation, where the math is relatively simple. The new work is based on a high-powered numerical lattice simulation which can probe much further into the complicated interactions at the end of inflation. The work shows more definitively than ever that a large class of models involving multiple forms of matter are in excellent agreement with observations.

The Least Understood Part of the Story

There are hundreds of proposals for producing the inflationary phase, but the transition between the inflationary phase and the so-called hot big bang is the least understood part of the story, says Richard Easther, professor of physics at the University of Auckland, who was not involved in the research. This paper breaks new ground by accurately simulating the postinflationary phase in models with many individual fields and complex kinetic terms. These are extremely challenging numerical simulations, and extend the state of the art for studies of nonlinear dynamics in the very early universe.

The Daily Galaxy, edited by Max Goldberg, via MIT News

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