Category Archives: Quantum Physics
Quantum Politics: Schrdinger Joe and the GOP War on Science – Daily Kos
For a party so dedicated for so many years to attacks on science climate change denial, vaccine disinformation, oldies but goodies like the creation vs. evolution brouhaha, new classics like ivermectin as a miracle COVID cure the GOP undeniably has found one area of science it loves: quantum physics.
You are in all likelihood aware of Schrdingers cat, the infamous feline that exists simultaneously alive and dead, the result of a sealed box, a poison gas capsule, and the indeterminate-until-observed nature of the universe at the quantum level. Einstein could not believe in this state of affairs, but for todays Republican party and the vast right-wing media ecosphere no problem!
The GOP has in fact succeeded at something many physicists would say is not possible: causing an actual human being to exist in a state of quantum superposition, said human being no less than the President of the United States, Joseph R. Biden. Biden exists now at least in the fevered imagination of self-proclaimed conservatives in two mutually incompatible states: doddering old man clearly suffering from dementia, and Machiavellian mastermind who has spent years leading a corrupt crime family while also manipulating the fabled Deep State into unleashing sham investigations and bogus trials against his political enemies.
Both of these things cannot be true, of course, but perhaps it is pointless to argue this with the Biden-haters because to them, both Bidens are possible. In fact, for political purposes, both Bidens are necessary: the President exists in that state of quantum indeterminacy until observed by a conservative, at which point the wave function collapses and Biden resolves into whichever version serves the rhetorical needs of the moment.
I dont know if Erwin Schrdinger loved cats, hated them, or was indifferent. But there is no doubt about the GOPs state of mind against President Biden: a poisonous mixture of hate and fear, unleashed at rallies and in political ads and TV interviews in whatever ratio necessary to conjure the imagined Biden they want their audience to see. There is no other outcome of this wave function, at least in our level of the multiverse. They hate and fear him, and as a result will stop at nothing to demonize and belittle him, mutually contradictory impulses (Hes a menace to America and the rule of law! Hes pathetic and feeble!) fed by the same stream of desperation, misplaced rage, and self-delusion.
Of course, if a conservative doesnt want to appear sympathetic to science as a result of their belief in Bidens impossible dual nature, they can cite poetry as their source of inspiration instead. Walt Whitman once wrote Do I contradict myself? Very well then, I contradict myself (I am large, I contain multitudes).
But then again, Whitman is now held as a queer icon, so perhaps the conservatives will stick to the physics.
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Quantum Politics: Schrdinger Joe and the GOP War on Science - Daily Kos
Faster Than the Speed of Light: Information Transfer Through Spooky Action at a Distance at the Large Hadron Collider – SciTechDaily
The inside of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider. Rochester physicists working at the detector have observed spin entanglement between top quarks and top antiquarks persisting at long distances and high speeds. Credit: CERN
Physicists have demonstrated quantum entanglement in top quarks and their antimatter partners, a discovery made at CERN. This finding extends the behavior of entangled particles to distances beyond the reach of light-speed communication and opens new avenues for exploring quantum mechanics at high energies.
An experiment by a group of physicists led by University of Rochester physics professor Regina Demina has produced a significant result related to quantum entanglementan effect that Albert Einstein called spooky action at a distance.
Entanglement concerns the coordinated behavior of minuscule particles that have interacted but then moved apart. Measuring propertieslike position or momentum or spinof one of the separated pair of particles instantaneously changes the results of the other particle, no matter how far the second particle has drifted from its twin. In effect, the state of one entangled particle, or qubit, is inseparable from the other.
Quantum entanglement has been observed between stable particles, such as photons or electrons.
But Demina and her group broke new ground in that they found, for the first time, entanglement to persist between unstable top quarks and their antimatter partners at distances farther than what can be covered by information transferred at the speed of light. Specifically, the researchers observed spin correlation between the particles.
Hence, the particles demonstrated what Einstein described as spooky action at a distance.
The finding was reported by the Compact Muon Solenoid (CMS) Collaboration at the European Center for Nuclear Research, or CERN, where the experiment was conducted.
Confirming the quantum entanglement between the heaviest fundamental particles, the top quarks, has opened up a new avenue to explore the quantum nature of our world at energies far beyond what is accessible, the report read.
CERN, located near Geneva, Switzerland, is the worlds largest particle physics laboratory. Production of top quarks requires very high energies accessible at the Large Hadron Collider (LHC), which enables scientists to send high-energy particles spinning around a 17-mile underground track at close to the speed of light.
The phenomenon of entanglement has become the foundation of a burgeoning field of quantum information science that has broad implications in areas like cryptography and quantum computing.
Top quarks, each as heavy as an atom of gold, can only be produced at colliders, such as LHC, and thus are unlikely to be used to build a quantum computer. But studies like those conducted by Demina and her group can shed light on how long entanglement persists, whether it is passed on to the particles daughters or decay products, and what, if anything, ultimately breaks the entanglement.
Theorists believe that the universe was in an entangled state after its initial fast expansion stage. The new result observed by Demina and her researchers could help scientists understand what led to the loss of the quantum connection in our world.
Demina recorded a video for CMS social media channels to explain her groups result. She used the analogy of an indecisive king of a distant land, whom she called King Top.
King Top gets word that his country is being invaded, so he sends messengers to tell all the people of his land to prepare to defend. But then, Demina explains in the video, he changes his mind and sends messengers to order the people to stand down.
He keeps flip flopping like this, and nobody knows what his decision will be at the next moment, Demina says.
Nobody, Demina goes on to explain, except the leader of one village in this kingdom who is known as Anti-Top.
They know each others state of mind at any moment in time, Demina says.
Deminas research group consists of herself and graduate student Alan Herrera and postdoctoral fellow Otto Hindrichs.
As a graduate student, Demina was on the team that discovered the top quark in 1995. Later, as a faculty member at Rochester, Demina co-led a team of scientists from across the US that built a tracking device that played a key role in the 2012 discovery of the Higgs bosonan elementary particle that helps explains the origin of mass in the universe.
Rochester researchers have a long history at CERN as part of the CMS Collaboration, which brings together physicists from around the globe. Recently, another Rochester team achieved a significant milestone in measuring the electroweak mixing angle, a crucial component of the Standard Model of Particle Physics, which explains how the building blocks of matter interact.
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The Road to Error-Free Quantum Computing – AZoQuantum
Jun 24 2024Reviewed by Lexie Corner
In a studypublished in PeerJ Computer Science, Professor Kazuhiro Ogataand Assistant Professor Canh Minh Do of the Japan Advanced Institute of Science and Technology (JAIST) suggested using symbolic model checking to validate quantum circuits.
Quantum computing is a fast-developing technology that utilizes the principles of quantum physics to tackle complicated computational problems that are extremely difficult for classical computing.
To take advantage of quantum computing, researchers worldwide have created a large number of quantum algorithms that show notable gains over classical algorithms.
Creating these algorithms requires the use of quantum circuits, which are models of quantum processing. Before they are actually deployed on quantum hardware, they are utilized to design and implement quantum algorithms.
Quantum circuits consist of a series of quantum gates, measurements, and qubit initializations, among other events. Quantum gates execute quantum computations by working on qubits, the quantum equivalents of conventional bits (0s and 1s), and manipulating the system's quantum states.
Quantum states are the output of quantum circuits that can be monitored to provide classical outcomes with probabilities from which additional actions can be taken. Since quantum computing is frequently counterintuitive and substantially distinct from classical computing, the likelihood of mistakes is significantly larger. As a result, it is critical to ensure that quantum circuits have the correct features and perform as planned.
This can be accomplished using model checking, a formal verification approach used to ensure that systems meet desirable attributes. Although certain model checkers are specialized to quantum programs, there is a distinction between model-checking quantum programs and quantum circuits due to differences in representation and the absence of iterations in quantum circuits.
Considering the success of model-checking methods for verification of classical circuits, model-checking of quantum circuits is a promising approach. We developed a symbolic approach for model checking of quantum circuits using laws of quantum mechanics and basic matrix operations using the Maude programming language.
Canh Minh Do, Assistant Professor, Japan Advanced Institute of Science and Technology
Maude is a high-level specification/programming language based on rewriting logic that enables the formal definition and verification of complicated systems. It comes with a Linear Temporal Logic (LTL) model checker that determines if systems meet the necessary features. Maude also enables the development of exact mathematical models of systems.
Using the Dirac notation and the rules of quantum physics, the researchers formally defined quantum circuits in Maude as a set of quantum gates and measurement applications. They provided the systems intended attributes and its initial state in LTL.
By using a set of quantum physics laws and basic matrix operations formalized in our specifications, quantum computation can be reasoned in Maude.The researchers then automatically checked whether quantum circuits satisfied the required characteristics using the integrated Maude LTL model checker.
Using this method, several early quantum communication protocols, each with increasing complexity, were checked: Superdense Coding, Quantum Teleportation, Quantum Secret Sharing, Entanglement Swapping, Quantum Gate Teleportation, Two Mirror-image Teleportation, and Quantum Network Coding.
They discovered that the initial iteration did not meet the desired property of Quantum Gate Teleportation. By employing this method, the researchers suggested an updated version and verified that it was accurate.
These findings highlight the significance of the suggested novel technique for the verification of quantum circuits. However, the researchers highlight certain drawbacks of their strategy that need more investigation.
Dr. Do added, In the future, we aim to extend our symbolic reasoning to handle more quantum gates and more complicated reasoning on complex number operations. We also would like to apply our symbolic approach to model-checking quantum programs and quantum cryptography protocols.
Verifying the expected functionality of quantum circuits will be extremely useful in the approaching era of quantum computing. In this context, the current technique is the first step toward a broader framework for verifying and specifying quantum circuits, opening the way for error-free quantum computing.
The study was supported by JST SICORP Grant Number JPMJSC20C2, Japan, and JSPS KAKENHI Grant Numbers JP23H03370, JP23K19959, and JP24K20757.
Do, C. M., etal. (2024) Symbolic model checking quantum circuits in Maude. PeerJ Computer Science. doi:10.7717/peerj-cs.2098
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Sugar-coating quantum systems to harvest science – EurekAlert
image:
Schematic of a hybrid cavity architecture to achieve efficient light-matter coupling. This design consists in a metasurface, formed of metallic cross-shaped array, onto which a thin film of organic material (glucose) is deposited. A mirror located above the metasurface ensures that light is trapped to form a photonic mode (rainbow colored beam) strongly interacting with glucose.
Credit: University of Ottawa
A team of international scientists led by the University of Ottawa have gone back to the kitchen cupboard to create a recipe that combines organic material and light to create quantum states.
Professor Jean-Michel Mnard, leader of the Ultrafast Terahertz Spectroscopy group at the Faculty of Science, coordinated with Dr. Claudiu Genes at the Max Planck Institute for the Science of Light (Germany), and with Iridian Spectral Technologies (Ottawa) to design a device which can efficiently modify properties of materials using the quantum superposition with light.
The team designed a two-dimensional planar resonator known as a metasurface that captured light. Using a spray coating technique, they then deposited a thin glucose layer on that metasurface to induce a strong interaction between light and glucose molecules in sugar.
Their concept brings researchers closer to being technologically able to harvest some of the unique properties of quantum systems falling in a hybrid state of both light and matter.
Faculty of Science professors Ksenia Dolgaleva and Robert Boyd contributed to the work alongside Professor Menard, the lead author, who discusses the findings published in Nature Communications.
Question: What did you set out to do and what did you find? Jean-Michel Mnard: We present an innovative and efficient technique for synthesizing quantum organic materials by combining light and matter. When light in the far-infrared region at terahertz (THz) frequencies becomes trapped within an organic material, it can merge with molecules, resulting in a quantum state that exhibits unique properties which are of growing interest because of their potential application in modifying the physical and chemical properties of matter. These intriguing states only arise under specific conditions. Our team identified these critical conditions and created a photonic trap or device to effectively confine light within a small volume space during a substantial amount of time. This trap enables a strong coupling regime to be established between light and a molecular ensemble.
Unlike previous approaches that relied on optical cavities made of two facing mirrors, we instead designed and tested a two-dimensional planar resonator known as a metasurface. This metasurface effectively allows optical confinement within a planar geometry, opening new practical avenues to explore the quantum regime of strong light-matter interactions.
Finally, we combined metasurfaces with traditional cavity geometries to form hybrid cavity architectures and observe an enhancement of the coupling strength between light and matter. These results are demonstrated with glucose, an organic compound with properties useful to the fields of biology and medicine.
Q: Why use THz light and sugar? JM: Terahertz light is particularly interesting because it can induce vibrations in many molecules, including glucose molecules in sugar. The energy of vibration of molecules is intricately connected to their properties including their ability to engage in chemical reactions with other molecules. Therefore, by designing platforms enabling a strong coupling between terahertz light and the vibration of molecules, which are fundamental building blocks of organic substances, we have the potential to change their properties to potentially gain control over mechanisms at the foundation of life.
Q: What did you ultimately find through your research? JM: We discovered efficient approaches to couple terahertz light and matter. The most promising concept is based on a structured metallic surface, the metasurface, incorporated into the design of a photonic cavity. As a result, light becomes doubly trapped and remains tightly confined within the device.
Our robust plug-and-play platform allows potentially many organic materials to be inserted inside this device to create quantum systems with new properties. This is due to the fact that no precise alignment of the device is required to trap the light as this critical condition is mostly fulfilled by the geometry of the metasurfaces metallic pattern. Interestingly, since scalable fabrication techniques exist to fabricate metasurfaces interacting with terahertz light, we believe that these devices could be used relatively soon for real-life applications of quantum-enhanced chemical reactions.
Q: What kind of impact can this research have? JM: "These results bring us closer to being technologically able to harvest some of the unique properties of quantum systems consisting of a hybridized state of light and matter. By performing a systematic theoretical and experimental study of different types of photonic resonators, we discovered some novel photonic resonator designs that can create a quantum superposition between a molecular material, glucose, and light in a specific region of the far-infrared spectral window called the terahertz region. Previous work demonstrated that this hybridization process, when it involves terahertz light, modifies the original physical and chemical properties of the material. For example, the presence of a photonic resonator can change the rate of some chemical reactions involving that material.
In the future, we believe this approach could help regulate some molecular processes, leading to application in medicine for rapid diagnostics and potentially new therapeutic strategies.
Nature Communications
Experimental study
Not applicable
Hybrid architectures for terahertz molecular polaritonics
24-May-2024
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Sugar-coating quantum systems to harvest science - EurekAlert
Time May Actually Be One Big Illusion, Says a New Study – AOL
Time May Actually Be One Big IllusionJuana Mari Moya - Getty Images
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Could the observable universe be exclusively composed of layered, mutually entangled systems?
The passage of time puzzles quantum physicists, who seek to fit it into a cohesive model.
One wild theory posits that time visibly passes because were entangled with... well... everything.
Time has puzzled scientists for many decades. Does it meaningfully exist apart from our experience of it as everything moves toward the disintegration of entropy along its irrefutable arrow? You cant put the spilled milk of the weirdness of time back in the jug.
In new research published in the American Physical Society's peer-reviewed journal Physical Review A, scientists from Italy (led by Alessandro Coppo) try to translate one theory of time into real lifeor, at least, closer to it. The theory is called Page and Wootters mechanism, and Coppo has studied it for years. Its a quantum mechanics idea that dates back to 1983.
While general relativity (in the classical physics model) lets time be a variablelike the perception-dependent difference between time on Earth and time in space in stories like Interstellarquantum physics requires it to be nailed down. That means instead of a dependent variable (something defined by an external property, like local gravity or an objects distance from Earth), time must be independent, and there must be some way to measure it as such.
This may seem counterintuitive. After all, quantum mechanics is considered the newer version of thingsthe one that destabilizes the foundation of physics in order to be reconciled with the classical model. But time has a unique role in quantum systems. After all, everything in a particular time, defined in some objective way, is knitted together through quantum interactions until it forms a capture of the entire universe (if you zoom out enough).
In their paper, Coppo and his coauthors turn the Page and Wootters approach into a real concept for a clock. Within quantum physics, a clock isnt much like the one you wear on your wrist or hang in your officeits anything that has a predictable and uniform behavior that can be used as a measurement. (For example, this 2021 Quanta article lists increasingly stinky garbage as a kind of clock!)
New Scientist explains that Page and Wootters wondered if our world is so quantumly entangled within itself that any visible passing of time is a symptom of entanglement. They also suggested that we ourselves are implicated in that entanglement just by seeing the passage of timebecause someone outside of the entangled system would see it standing still. The clock, therefore, is the item within the entangled system that shows time passing.
Its easy to see why this theory has stayed mostly abstract for over 40 years. To turn it into something with measurements based in real life observation, scientists took iconic physics equations and restricted them to conditions that match the Page and Wootters scenario. They considered two systems that are entangled but do not interact, where one system is a harmonic oscillatorlike a quartz timing in a watch, or a pendulum.
Their solution may prove to be consistent within classical and quantum mechanics, because when enough particles are placed into each quantum systemwhen it reaches the threshold called macroscopic, based on massthe systems align with classical physics as well.
Thats a big dealif our entire, very macroscopic world fits into this definition of time based on entanglement, it means everything around us is entangled. Things would need to be entangled almost by definition in order to be part of our observable world. And it would mean that anything we see where time passes (no matter how far away it is) is linked with us in a vital way.
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Time May Actually Be One Big Illusion, Says a New Study - AOL
Silicon Magic: Powering the Quantum Internet of the Future – SciTechDaily
By Leah Burrows, Harvard John A. Paulson School of Engineering and Applied Sciences June 23, 2024
The device uses a simple electric diode to manipulate qubits inside a commercial silicon wafer. Credit: Second Bay Studios/Harvard SEAS
By utilizing traditional semiconductor devices, researchers have unlocked new potentials in quantum communication, pushing us closer to realizing the vast potential of the quantum internet.
Building the quantum internet could be significantly simplified by leveraging existing telecommunications technologies and infrastructure. In recent years, researchers have identified defects in silicona widely used semiconductor materialthat hold the potential for transmitting and storing quantum information across the prevalent telecommunications wavelengths. These silicon defects might just be the prime contenders to host qubits for efficient quantum communications.
Its still a Wild West out there, said Evelyn Hu, the Tarr-Coyne Professor of Applied Physics and of Electrical Engineering at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS). Even though new candidate defects are a promising quantum memory platform, there is often almost nothing known about why certain recipes are used to create them, and how you can rapidly characterize them and their interactions, even in ensembles. And ultimately, how can we fine-tune their behavior so they exhibit identical characteristics? If we are ever to make a technology out of this wide world of possibilities, we must have ways to characterize them better, faster, and more efficiently.
Now, Hu and a team of researchers have developed a platform to probe, interact with and control these potentially powerful quantum systems. The device uses a simple electric diode, one of the most common components in semiconductor chips, to manipulate qubits inside a commercial silicon wafer. Using this device, the researchers were able to explore how the defect responds to changes in the electric field, tune its wavelength within the telecommunications band and even turn it on and off.
If we are ever to make a technology out of this wide world of possibilities, we must have ways to characterize them better, faster and more efficiently.
Evelyn Hu, Tarr-Coyne Professor of Applied Physics and of Electrical Engineering
One of the most exciting things about having these defects in silicon is that you can use well-understood devices like diodes in this familiar material to understand a whole new quantum system and do something new with it, said Aaron Day, a Ph.D. candidate at SEAS. Day co-led the work with Madison Sutula, a research fellow at Harvard.
While the research team used this approach to characterize defects in silicon, it could be used as a diagnostic and control tool for defects in other material systems.
The research is published in Nature Communications.
Quantum defects, also known as color centers or quantum emitters, are imperfections in otherwise perfect crystal lattices that can trap single electrons. When those electrons are hit with a laser, they emit photons in specific wavelengths. The defects in silicon that researchers are most interested in for quantum communications are known as G-centers and T-centers. When these defects trap electrons, the electrons emit photons in a wavelength called the O-band, which is widely used in telecommunications.
In this research, the team focused on G-center defects. The first thing they needed to figure out was how to make them. Unlike other types of defects, in which an atom is removed from a crystal lattice, G-center defects are made by adding atoms to the lattice, specifically carbon. But Hu, Day and the rest of the research team found that adding hydrogen atoms is also critical to consistently forming the defect.
Next, the researchers fabricated electrical diodes using a new approach that optimally sandwiches the defect at the center of every device without degrading the performance of either the defect or the diode. The fabrication method can create hundreds of devices with embedded defects across a commercial wafer. Hooking the whole device up to apply a voltage, or electric field, the team found that when a negative voltage was applied across the device, the defects turned off and went dark.
Understanding when a change in environment leads to a loss of signal is important for engineering stable systems in networking applications, said Day,
The scientists also found that by using a local electric field, they could tune the wavelengths being emitted by the defect, which is important for quantum networking when disparate quantum systems need to be aligned.
The team also developed a diagnostic tool to image how the millions of defects embedded in the device change in space as the electric field is applied.
We found that the way were modifying the electric environment for the defects has a spatial profile, and we can image it directly by seeing the changes in the intensity of light being emitted by the defects, said Day. By using so many emitters and getting statistics on their performance, we now have a good understanding of how defects respond to changes in their environment. We can use that information to inform how to build the best environments for these defects in future devices. We have a better understanding of what makes these defects happy and unhappy.
Next, the research team aims to use the same techniques to understand the T-center defects in silicon.
Reference: Electrical manipulation of telecom color centers in silicon by Aaron M. Day, Madison Sutula, Jonathan R. Dietz, Alexander Raun, Denis D. Sukachev, Mihir K. Bhaskar and Evelyn L. Hu, 3 June 2024, Nature Communications. DOI: 10.1038/s41467-024-48968-w
The research was co-authored by Sutula, Jonathan R. Dietz, Alexander Raun from SEAS, and AWS research scientists Denis D. Sukachev and Mihir K. Bhaskar.
This work was supported by AWS Center for Quantum Networking and the Harvard Quantum Initiative. Harvards Office of Technology Development has protected the intellectual property associated with this project and is pursuing commercialization opportunities.
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Silicon Magic: Powering the Quantum Internet of the Future - SciTechDaily
String Theory Unravels New Pi Formula: A Quantum Leap in Mathematics – SciTechDaily
Scientists discovered a new series for pi through string theory research, echoing a 15th-century formula by Madhava. By combining Euler-Beta Functions and Feynman Diagrams, they modeled particle interactions efficiently. Credit: SciTechDaily.com
Researchers found a new series representation for pi while exploring string theory and particle interactions.
Their formula is similar to one by Madhava in the 15th century. Combining the Euler-Beta Function and Feynman Diagram, they created an efficient model, revealing this new pi representation. Theoretical work like this can eventually lead to practical applications.
While investigating how string theory can be used to explain certain physical phenomena, scientists at the Indian Institute of Science (IISc) have stumbled upon a new series representation for the irrational number pi. It provides an easier way to extract pi from calculations involved in deciphering processes like the quantum scattering of high-energy particles.
The new formula under a certain limit closely reaches the representation of pi suggested by Indian mathematician Sangamagrama Madhava in the 15th century, which was the first ever series for pi recorded in history. The study was carried out by Arnab Saha, a post-doc and Aninda Sinha, Professor at the Centre for High Energy Physics (CHEP), and published in Physical Review Letters.
Aninda Sinha (left) and Arnab Saha (right). Credit: Manu Y
Our efforts, initially, were never to find a way to look at pi. All we were doing was studying high-energy physics in quantum theory and trying to develop a model with fewer and more accurate parameters to understand how particles interact. We were excited when we got a new way to look at pi, Sinha says.
Sinhas group is interested in string theory the theoretical framework that presumes that all quantum processes in nature simply use different modes of vibrations plucked on a string. Their work focuses on how high energy particles interact with each other such as protons smashing together in the Large Hadron Collider and in what ways we can look at them using as few and as simple factors as possible. This way of representing complex interactions belongs to the category of optimization problems. Modeling such processes is not easy because there are several parameters that need to be taken into account for each moving particle its mass, its vibrations, the degrees of freedom available for its movement, and so on.
Saha, who has been working on the optimization problem, was looking for ways to efficiently represent these particle interactions. To develop an efficient model, he and Sinha decided to club two mathematical tools: the Euler-Beta Function and the Feynman Diagram. Euler-Beta functions are mathematical functions used to solve problems in diverse areas of physics and engineering, including machine learning. The Feynman Diagram is a mathematical representation that explains the energy exchange that happens while two particles interact and scatter.
What the team found was not only an efficient model that could explain particle interaction, but also a series representation of pi.
In mathematics, a series is used to represent a parameter such as pi in its component form. If pi is the dish then the series is the recipe. Pi can be represented as a combination of many numbers of parameters (or ingredients). Finding the correct number and combination of these parameters to reach close to the exact value of pi rapidly has been a challenge. The series that Sinha and Saha have stumbled upon combines specific parameters in such a way that scientists can rapidly arrive at the value of pi, which can then be incorporated into calculations, like those involved in deciphering the scattering of high-energy particles.
Physicists (and mathematicians) have missed this so far since they did not have the right tools, which were only found through work we have been doing with collaborators over the last three years or so, Sinha explains. In the early 1970s, scientists briefly examined this line of research but quickly abandoned it since it was too complicated.
Although the findings are theoretical at this stage, it is not impossible that they may lead to practical applications in the future. Sinha points to how Paul Dirac worked on the mathematics of the motion and existence of electrons in 1928, but never thought that his findings would later provide clues to the discovery of the positron, and then to the design of Positron Emission Tomography (PET) used to scan the body for diseases and abnormalities. Doing this kind of work, although it may not see an immediate application in daily life, gives the pure pleasure of doing theory for the sake of doing it, Sinha adds.
Reference: Field Theory Expansions of String Theory Amplitudes by Arnab Priya Saha and Aninda Sinha, 28 May 2024, Physical Review Letters. DOI: 10.1103/PhysRevLett.132.221601
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String Theory Unravels New Pi Formula: A Quantum Leap in Mathematics - SciTechDaily
Scientists Discovered How to Control the Casimir Effectand Supercharge Tiny Machines – Popular Mechanics
In 1948, Dutch physicist Hendrik Casimirwho worked with one of the fathers of quantum physics, Neils Bohrdeveloped an ingenious experiment to witness the invisible (at least, to us) wonders of quantum mechanics. Casimir placed two electrically neutral plates within one micrometer of each other in a vacuum. Without any forces acting upon them, you might expect the plates to remain perfectly still but they didnt. Instead, the plates were pulled together via the invisible quantum fluctuations that permeate spacetime.
This experiment was a stunning display of the invisible quantum world, and this phenomenon became known, quite rightly, as the Casimir effect. Itd be another 50 years before the Yale physicist Steve Lamoreaux finally measured this incredibly small effect, but with the rise of nanotechnology during that same period, understanding the Casimir effect and how it would impact these incredibly small machines became vitally important. Sort of how the designs of satellites need to take our understanding of relativity into account, so too must nanotechnologies be designed with the Casimir effect in mind.
Now, in the next step toward understanding this incredible phenomenon, scientists from the Chinese Academy of Sciences have found a method of tuning this effect. Using a ferrofluida fluid that can be manipulated using magnetic fieldsas an intermediate medium, the researchers used magnetic fields to create a reversible transition from Casimir attraction to repulsion. The results of the study were published in late May in the journal Nature Physics.
The quantum fluctuation-induced Casimir force can be either attractive or repulsive, depending on the dielectric permittivities [the ability of a substance to store electrical energy in an electric field] and magnetic permeabilities of the materials involved, the paper reads. Our theoretical calculations predict that, by varying the magnetic field, separation distance and ferrofluid volume fraction, the Casimir force can be tuned from attractive to repulsive over a wide range of parameters in this system.
As the paper notes, its challenging to alter the dielectric permittivities of a material, but you can manipulate the permeabilities of ferrofluids with magnetic fields. This is how the researchers designed an experiment examining this kind of manipulation between a gold sphere and a silicon dioxide substrate. As predicted, the experiment allowed the researchers to accurately manipulate the Casimir attraction or repulsion of the two materials.
Gaining some kind of control over this incredibly small effect could have big implications for the creation of future nano- and micro-electromechanical devices. Of course, there are other ideas surrounding the Casimir effectalso known as vacuum energy or zero-point energyespecially as it plays a role in studying the black hole-based Hawking radiation that features prominently in discussions about warp bubbles and warp drives. But for now, its very large technological impact mostly pertains to the world of very small machines.
Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.
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Physicists Uncover New Path to Quantum Computing: Infrared Illumination – SciTechDaily
When irradiated with infrared light, certain molecules like metal phthalocyanines vibrate and generate tiny, localized magnetic fields. Researchers have calculated these effects and aim to experimentally prove and manipulate these fields for potential applications in quantum computing. Credit: SciTechDaily.com
Physicists at TU Graz have determined that certain molecules can be stimulated by pulses of infrared light to generate small magnetic fields. If experimental trials are also successful, this technique could potentially be applied in quantum computer circuits.
When molecules absorb infrared light, they start to vibrate as they receive energy. Andreas Hauser from the Institute of Experimental Physics at Graz University of Technology (TU Graz) used this well-understood process as a basis for exploring whether these vibrations could be harnessed to produce magnetic fields. Since atomic nuclei carry a positive charge, the movement of these charged particles results in the creation of a magnetic field.
Using the example of metal phthalocyanines ring-shaped, planar dye molecules Andreas Hauser and his team have now calculated that, due to their high symmetry, these molecules actually generate tiny magnetic fields in the nanometre range when infrared pulses act on them.
According to the calculations, it should be possible to measure the rather low but very precisely localized field strength using nuclear magnetic resonance spectroscopy. The researchers have published their results in the Journal of the American Chemical Society.
For the calculations, the team drew on preliminary work from the early days of laser spectroscopy, some of which were decades old. They also used modern electron structure theory on supercomputers at the Vienna Scientific Cluster and TU Graz to calculate how phthalocyanine molecules behave when irradiated with circularly polarized infrared light. What happened was that the circularly polarized, i.e. helically twisted, light waves excite two molecular vibrations at the same time at right angles to each other.
Andreas Hauser from the Institute of Experimental Physics at TU Graz. Credit: Lunghammer TU Graz
As every rumba dancing couple knows, the right combination of forwards-backwards and left-right creates a small, closed loop. And this circular movement of each affected atomic nucleus actually creates a magnetic field, but only very locally, with dimensions in the range of a few nanometres, says Andreas Hauser.
By selectively manipulating the infrared light, it is even possible to control the strength and direction of the magnetic field, explains Andreas Hauser. This would turn the molecules into high-precision optical switches, which could perhaps also be used to build circuits for a quantum computer.
Schematic representation of a metal phthalocyanine molecule that is set into two vibrations (red and blue), creating a rotating electric dipole moment (green) in the molecular plane and thus a magnetic field. Credit: Wilhelmer/Diez/Krondorfer/Hauser TU Graz
Together with colleagues from the Institute of Solid State Physics at TU Graz and a team at the University of Graz, Andreas Hauser now wants to prove experimentally that molecular magnetic fields can be generated in a controlled manner.
For proof, but also for future applications, the phthalocyanine molecule needs to be placed on a surface. However, this changes the physical conditions, which in turn influences the light-induced excitation and the characteristics of the magnetic field, explains Andreas Hauser. We therefore want to find a support material that has minimal impact on the desired mechanism.
In the next step, the physicist and his colleagues want to compute the interactions between the deposited phthalocyanines, the support material, and the infrared light before putting the most promising variants to the test in experiments.
Reference: Molecular Pseudorotation in Phthalocyanines as a Tool for Magnetic Field Control at the Nanoscale by Raphael Wilhelmer, Matthias Diez, Johannes K. Krondorfer and Andreas W. Hauser, 14 May 2024, Journal of the American Chemical Society. DOI: 10.1021/jacs.4c01915
The study was funded by the Austrian Science Fund.
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Physicists Uncover New Path to Quantum Computing: Infrared Illumination - SciTechDaily
Researching quantum theory, physicists stumble on new way to represent Pi – Ynetnews
Indian physicists Arnab Saha and Aninda Sinha from the Centre for High Energy Physics discovered a new series representation for calculating the irrational number while investigating string theory and quantum scattering of high-energy particles.
The new formula, which closely resembles a representation suggested by the Indian mathematician Sangamagrama Madhava in the 15th century, provides an easier way to extract from calculations involved in deciphering processes such as quantum scattering.
The study, published in Physical Review Letters, focused on simplifying calculations involved in high-energy particle interactions by combining the Euler-Beta Function and Feynman Diagram.
The new series representation allows scientists to rapidly obtain the value of for calculations involving particle scattering, potentially aiding in simplifying calculations for quantum processes.
Initially, the researchers were focusing on high-energy physics and developing models to understand particle interactions. Pi can be represented as a combination of various parameters, and finding the right mix quickly has been a challenge.
Sources: Times of India, Economic Times, phys.org, en.news4social.com
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Researching quantum theory, physicists stumble on new way to represent Pi - Ynetnews