Lifeboat Foundation

The Hubbard model is a studied model in condensed matter theory and a formidable quantum problem. A team of physicists used deep learning to condense this problem, which previously required 100,000 equations, into just four equations without sacrificing accuracy. The study, titled “Deep Learning the Functional Renormalization Group,” was published on September 21 in Physical Review Letters.

Dominique Di Sante is the lead author of this study. Since 2021, he holds the position of Assistant Professor (tenure track) at the Department of Physics and Astronomy, University of Bologna. At the same time, he is a Visiting Professor at the Center for Computational Quantum Physics (CCQ) at the Flatiron Institute, New York, as part of a Marie Sklodowska-Curie Actions (MSCA) grant that encourages, among other things, the mobility of researchers.

He and colleagues at the Flatiron Institute and other international researchers conducted the study, which has the potential to revolutionize the way scientists study systems containing many interacting electrons. In addition, if they can adapt the method to other problems, the approach could help design materials with desirable properties, such as superconductivity, or contribute to clean energy production.

Planck length and Planck time and quantum foam.

Space Emerging from Quantum.

The other day I was amused to find a quote from Einstein, in 1936, about how hard it would be to quantize gravity: “like an attempt to breathe in empty space.” Eight decades later, I think we can still agree that it’s hard.

Continue reading “Space Emerging from Quantum Mechanics” »

Artificially intelligent Maxwell’s demon for optimal control of open…

A team of researchers used reinforcement learning (RL) to optimize feedback control strategies in quantum systems.

I have my own introduction quantum mechanics course that you can check out on Brilliant! First 30 days are free and 20% off the annual premium subscription when you use our link ➜ https://brilliant.org/sabine.

Physicists are obsessed with black holes, but we still don’t know what’s going on inside of them. One idea is that black holes do not truly exist, but instead they are big quantum objects that have been called fuzzballs or frozen stars. This idea has a big problem. Let’s take a look.

Continue reading “These physicists say they know what’s inside a black hole” »

All physical observations are made relative to a reference frame, which is a system in its own right. If the system of interest admits a group symmetry, the reference frame observing it must transform commensurately under the group to ensure the covariance of the combined system. We point out that the crossed product is a way to realize quantum reference frames from the bottom-up; adjoining a quantum reference frame and imposing constraints generates a crossed product algebra. We provide a top-down specification of crossed product algebras and show that one cannot obtain inequivalent quantum reference frames using this approach. As a remedy, we define an abstract algebra associated to the system and symmetry group built out of relational crossed product algebras associated with different choices of quantum reference frames.

Recently Danielson, Satishchandran, and Wald (DSW) have shown that quantum superpositions held outside of Killing horizons will decohere at a steady rate. This occurs because of the inevitable radiation of soft photons (gravitons), which imprint a electromagnetic (gravitational) “which-path’’ memory onto the horizon. Rather than appealing to this global description, an experimenter ought to also have a local description for the cause of decoherence. One might intuitively guess that this is just the bombardment of Hawking/Unruh radiation on the system, however simple calculations challenge this idea—the same superposition held in a finite temperature inertial laboratory does not decohere at the DSW rate. In this work we provide a local description of the decoherence by mapping the DSW setup onto a worldline-localized model resembling an Unruh-DeWitt particle detector.

Quantum mechanics: it’s the realm of science where nothing is normal, and everything seems to undermine the fundaments of our common understanding of reality. Nonetheless, we simple humans tick on.

But quantum physicists, who pride themselves on staring into the abyss and gleaning its spooky secrets, have just discovered another baffling phenomenon to make your mind melt: “negative time.”

As detailed in a yet-to-be-peer-reviewed study covered by Scientific American, a team of researchers say they’ve observed photons exhibiting this bizarre temporal behavior as the result of what’s known as atomic excitation.

Physicists from the University of Basel have succeeded in coupling two Andreev qubits coherently over a macroscopic distance for the first time. They achieved this with the help of microwave photons generated in a narrow superconducting resonator. The results of the experiments and accompanying calculations were recently published in Nature Physics, laying the foundation for the use of coupled Andreev qubits in quantum communication and quantum computing.

The next generation of handheld devices requires a novel solution. Spintronics, or spin electronics, is a revolutionary new field in condensed-matter physics that can increase the memory and logic processing capability of nano-electronic devices while reducing power consumption and production costs. This is accomplished by using inexpensive materials and the magnetic properties of an electron’s spin to perform memory and logic functions instead of using the flow of electron charge used in typical electronics.

New work by Florida State University scientists is propelling spintronics research forward.

Professors Biwu Ma in the Department of Chemistry and Biochemistry and Peng Xiong in the Department of Physics work with low-dimensional organic metal halide hybrids, a new class of hybrid materials that can power optoelectronic devices like solar cells, light-emitting diodes, or LEDs and photodetectors.