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Researchers have used quantum computers to solve difficult physics problems. But claims of a quantum “advantage” must wait as ever-improving algorithms boost the performance of classical computers.

Quantum computers have plenty of potential as tools for carrying out complex calculations. But exactly when their abilities will surpass those of their classical counterparts is an ongoing debate. Recently, a 127-qubit quantum computer was used to calculate the dynamics of an array of tiny magnets, or spins—a problem that would take an unfathomably long time to solve exactly with a classical computer [1]. The team behind the feat showed that their quantum computation was more accurate than nonexact classical simulations using state-of-the-art approximation methods. But these methods represented only a small handful of those available to classical-computing researchers. Now Joseph Tindall and his colleagues at the Flatiron Institute in New York show that a classical computer using an algorithm based on a so-called tensor network can produce highly accurate solutions to the spin problem with relative ease [2].

Scientists used a laser-based technique to reveal hidden quantum properties of the material Ta2NiSe5, potentially advancing the development of quantum light sources.

Certain materials have desirable properties that are hidden, and just as you would use a flashlight to see in the dark, scientists can use light to uncover these properties.

Researchers at the University of California San Diego have used an advanced optical technique to learn more about a quantum material called Ta₂NiSe₅ (TNS). Their work was published in the journal Nature Materials.

When a high-energy photon strikes a proton, secondary particles diverge in a way that indicates that the inside of the proton is maximally entangled. An international team of physicists with the participation of the Institute of Nuclear Physics of the Polish Academy of Sciences in Cracow has just demonstrated that maximum entanglement is present in the proton even in those cases where pomerons are involved in the collisions.

Eighteen months ago, it was shown that different parts of the interior of the proton must be maximally quantum entangled with each other. This result, achieved with the participation of Prof. Krzysztof Kutak from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Cracow and Prof. Martin Hentschinski from the Universidad de las Americas Puebla in Mexico, was a consequence of considerations and observations of collisions of high-energy photons with quarks and gluons in protons and supported the hypothesis presented a few years earlier by professors Dimitri Kharzeev and Eugene Levin.

Now, in a paper published in the journal Physical Review Letters, an international team of physicists has presented a complementary analysis of entanglement for collisions between photons and protons in which secondary particles (hadrons) are produced by a process called diffractive deep inelastic scattering. The main question was: does entanglement also occur among quarks and gluons in these cases, and if so, is it also maximal?

4 reviewer reports (4 anonymous)

13 citations in the Web of Science Core Collection.

Classical and Quantum Gravity Published by IOP Publishing Indexed in the Web of Science Core Collection Engages in Transparent Peer Review.

Jonathan Oppenheim at University College London has developed a new theoretical framework that aims to unify quantum mechanics and classical gravity – without the need for a theory of quantum gravity. Oppenheim’s approach allows gravity to remain classical, while coupling it to the quantum world by a stochastic (random) mechanism.

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For decades, theoretical physicists have struggled to reconcile Einstein’s general theory of relativity – which describes gravity — with quantum theory, which describes just about everything else in physics. A fundamental problem is that quantum theory assumes that space–time is fixed, whereas general relativity says that space–time changes dynamically in response to the presence of massive objects.

In 1948, Schwinger developed a local Lorentz-covariant formulation of relativistic quantum electrodynamics in space-time which is fundamentally inconsistent with any delocalized interpretation of quantum mechanics. An interpretation compatible with Schwinger’s theory is presented, which reproduces all of the standard empirical predictions of conventional delocalized quantum theory in configuration space. This is an explicit, unambiguous, and Lorentz-covariant “local hidden variable theory” in space-time, whose existence proves definitively that such theories are possible. This does not conflict with Bell’s theorem because it is a local many-worlds theory.

Year 2021 face_with_colon_three Basically this is a quantum computer that time travel within the computer so it can do processing faster.

Formed inside superfluid helium-3, the time crystals were observed for a record time of over 15 minutes.

Albert Einstein was one smart cookie; there’s no doubt about it. But even he knew his general theory of relativity – the 21st century’s answer to Newton’s universal theory of gravity – wasn’t perfect.

Like the second-hand car you bought using your first paycheck, it does the job for day-to-day errands. Push it too hard up a steep hill or park it near a quantum strip mall, and that engine shudders to a standstill.

Peoples’ Friendship University of Russia astrophysics grad student Hamidreza Fazlollahi’s solution is to dive under the hood and see which components aren’t as essential as they seem.

In 1,859, French astronomer and mathematician Urbain Le Verrier detected something strange: Mercury deviated in its dance around the Sun, defying the orderly precession predicted by Newtonian physics.

This odd anomaly couldn’t be explained by unknown planets tugging at Mercury’s orbit; only by physicist Albert Einstein’s 1915 general theory of relativity, which describes how gravity creates curves in the fabric of space-time.

Einstein’s general theory has held strong in the century since, but there are a few things about the Universe his mind-bending model can’t explain. It breaks down in the centers of black holes and at the dawn of the Universe, for example, and doesn’t fit very easily with quantum mechanics, leading some physicists to ponder alternative takes on how gravity works.