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Measuring a photon’s angular momentum after it passes through optical devices teaches an algorithm to reconstruct the properties of the photon’s initial quantum state.

A quantum squeezing method can enhance interactions between quantum systems, even in the absence of precise knowledge of the system parameters.

Squeezed states are an important class of nonclassical states, where quantum fluctuations can be reduced in one property of a system, such as position. However, at the same time, according to the Heisenberg uncertainty principle, quantum fluctuations increase in the conjugate property, in this case momentum. The ability to suppress noise in at least one variable is valuable in a wide range of areas in quantum technologies. Now Shaun Burd at the National Institute of Standards and Technology, Colorado, and colleagues have experimentally demonstrated a squeezing-based enhancement method that requires no preknowledge of the system’s parameters [1]. The researchers use a trapped-ion system (Fig. 1) and show that they can amplify the motion of the ion using a combination of squeezing procedures. This experimental research can stimulate other novel applications of squeezing, for example, in dark matter searches.

For decades, quantum squeezing has played a central role in high-precision quantum measurements, such as gravitational-wave detection [2, 3] and nondemolition qubit readout [4– 6]. The methods typically involve applying a field or inserting an optical element that reduces the fluctuations in one observable. The measurements of this squeezed observable can beat the standard quantum limit and thus enable a significant improvement in the detection sensitivity or the readout signal-to-noise ratio.

A numerical investigation has revealed a surprising correspondence between a lattice spin model and a quantum field theory.

The search for a quantum spin liquid (QSL) in a real magnetic material has been at the forefront of condensed-matter physics since this exotic quantum state was first proposed over half a century ago. Meanwhile, theorists continue to grapple with understanding what rich physics might emerge from this state. Now Alexander Wietek of the Max Planck Institute for the Physics of Complex Systems in Germany and his collaborators have made a significant advance toward that goal. Through numerical simulations, they have presented a compelling numerical case that the spectrum of elementary excitations of a well-studied QSL has a one-to-one correspondence with the spectrum of excitations of a well-studied quantum field theory [1]. If a real QSL is discovered or fabricated, the correspondence opens the prospect of testing theories from particle physics with condensed-matter systems.

Intrinsically stretchable quantum dot light-emitting diodes. Credit: Institute for Basic Science.

Intrinsically stretchable quantum dot-based light-emitting diodes achieved record-breaking performance.

A team of South Korean scientists led by Professor KIM Dae-Hyeong of the Center for Nanoparticle Research within the Institute for Basic Science has pioneered a novel approach to stretchable displays. The team announced the first development of intrinsically stretchable quantum dot light-emitting diodes (QLEDs).

Study shows neutrons can bind to nanoscale atomic clusters known as quantum dots. The finding may provide insights into material properties and quantum effects.

Neutrons are subatomic particles that have no electric charge, unlike protons and electrons. That means that while the electromagnetic force is responsible for most of the interactions between radiation and materials, neutrons are essentially immune to that force.

Neutron interaction through the strong force.

Rice University physicists have discovered a phase-changing quantum material — and a method for finding more like it — that could potentially be used to create flash-like memory capable of storing quantum bits of information, or qubits, even when a quantum computer is powered down.

Phase-Changing Materials and Digital Memory

Phase-changing materials have been used in commercially available non-volatile digital memory. In rewritable DVDs, for example, a laser is used to heat minute bits of material that cools to form either crystals or amorphous clumps. Two phases of the material, which have very different optical properties, are used to store the ones and zeros of digital bits of information.

An international research team led by the University of Göttingen has demonstrated experimentally that electrons in naturally occurring double-layer graphene move like particles without any mass, in the same way that light travels. Furthermore, they have shown that the current can be “switched” on and off, which has potential for developing tiny, energy-efficient transistors—like the light switch in your house but at a nanoscale.

Check out the math & physics courses that I mentioned (many of which are free!) and support this channel by going to https://brilliant.org/Sabine/ where you can create your Brilliant account. The first 200 will get 20% off the annual premium subscription. In the diagram at 4 minutes 30 seconds, the labels for h_1 and h_2 are mixed up. Sorry about that! Subscribe to my weekly science newsletter: https://sabinehossenfelder.com/ Everything I am talking about here is standard material of undergrad physics textbooks. My personal favorite is good old Goldstein https://en.wikipedia.org/wiki/Classic… On variational principles more specifically I quite like this textbook: https://link.springer.com/book/10.100… You can support me on Patreon: / sabine 0:00 Intro 0:45 Optimization 1:35 Shortest Path 3:20 Least Time 5:36 Least Action 10:27 Quantum Mechanics 11:53 Sponsor Message.

I found this on NewsBreak: Scientists Use Lasers to Induce Magnetism at Room Temperature, Defying Conventional Quantum Limits.