Advances in spin-based quantum sensors are opening new frontiers in precision “table-top” tests of fundamental physics, complementary to the approaches pursued in high-energy experiments.

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The authors optically analyze the torsional mechanical modes of a tapered optical fiber. The observed quality factor of the fundamental mode of the fiber waist is as large as 10${}^7$ and the $Qf$ product of 1 THz is promisingly close to the threshold value of 6 THz, required for room-temperature quantum optomechanics. Using feedback cooling, the authors cool the motional temperature of the torsional mode from room temperature to only 30 mK.

The authors present a theoretical analysis of a frequency-chirped molecular magneto-optical trap (MOT) that may open the way for efficient cooling of a class of light molecules. They show that this approach can increase the capture velocity of the MOT which could be used to capture more molecules from typical molecular sources and, in some cases, perhaps remove the need for laser slowing before capture in the MOT.

Quantum error mitigation involves reducing errors in hybrid quantum-classical algorithms, which is particularly relevant for near-term noisy quantum devices. The authors introduce an error mitigation technique based on redundant parity encoding of logical variables. They demonstrate the use of this technique by applying it to the quantum approximate optimization algorithm.

According to the Schiff theorem, an external electric field on the atomic nucleus is completely shielded by electrons. However, in the present paper, it is shown that, in a nonstationary state of atoms and molecules, the electric field on the nucleus is not zero. It may affect nuclear reactions and interact with nuclear electric dipole moment.

The authors demonstrate that certain solutions to the two-qubit quantum Rabi and Jaynes-Cummings models can be used to implement a high-quality deterministic single-photon source in the ultrastrong-coupling regime.

The propagation of slow light encodes the universal features of a strongly interacting impurity in a Bose-Einstein condensate. The author proposes the use of polariton physics as a nondestructive measurement tool for impurity physics and to investigate polaron physics in the single-impurity limit.

The authors use microwave spectroscopy to measure the quantum defects for lower-$l$ singlet strontium Rydberg states at intermediate $n$. The results are used to develop a revised set of Rydberg-Ritz quantum defect parameters that could help make accurate predictions of the energy intervals between other high-lying states.

The authors propose a scheme to measure the non-Abelian gauge field through multiloop evolution and robust holonomic quantum gates, and experimentally demonstrate it in the degenerate eigensubspace of a double-$\mathrm{\Lambda }$ four-level atomic system of ${}^{87}$Rb. The results could be useful for the development of high-resolution and high-precision measurements of the gauge fields.

While earlier research has predicted that maximally entangled single-particle states (MESPS), i.e., entanglement between different degrees of freedom of the same particle, can occur using quantum walk schemes with two or more coins or with a coin and identity operation, the authors analytically predict that MESPS can be generated using only a single coin on cyclic graphs. The generated MESPS occurs at recurring time steps, an advantage the authors exploit in a quantum cryptographic protocol.

Using two entangled photons of different colors in a Hong-Ou-Mandel interference scheme, the authors show that they can precisely measure the thickness of a semitransparent sample. The depth sensitivity is adjustable and the method is resilient against fluctuations commonly encountered in biological samples.

View an interview with PRX Life Lead Editor Margaret Gardel and Managing Editor Serena Bradde from the 2023 APS March Meeting for more information on the journal.

Three journals are excited to announce a new article type, “Perspectives,” to provide forward-looking views of cutting-edge science that has recently emerged or is enjoying renewed activity.

We are very pleased to offer the readers of Physical Review a new, carefully curated collection of articles from the vibrant field of laser-plasma particle acceleration. Some of the articles have already been published, and others will be forthcoming. This Collection is the latest in the journal’s series of Special Collections on current or emerging fields and topics.

Physicists working in optics, atomic and molecular physics, and quantum information reflect on landmark papers and how they influence research today.

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