Spectrum of an intense few-cycle light pulse as it crosses from vacuum (left of orange line) into a resonant nonlinear medium (right) and stops.

On May 27, Hauke Biss, Universität Hamburg, Germany, sits down with the Physical Review Journal Club to discuss the recently published PRL paper “Excitation Spectrum and Superfluid Gap of an Ultracold Fermi Gas.” Biss and colleagues utilized Bragg spectroscopy to measure the full momentum-resolved low-energy excitation spectrum of strongly interacting ultracold Fermi gases. This technique enabled the team to directly observe the smooth transformation from a bosonic to a fermionic superfluid that takes place in the BEC-BCS crossover. The team also used spectra to determine the evolution of the superfluid gap and find excellent agreement with previous experiments and self-consistent T-matrix calculations both in the BEC and crossover regime. However, toward the BCS regime a calculation that includes the effects of particle-hole correlations shows better agreement with the presented data. The research was summarized in Physics Magazine.

Biss will present the team’s data, then will join collaborators to answer all participant questions in a live question-and-answer session where all participant questions will be answered.

Registration is free and a recording of the session will be provided to all registrants.

Reflectionless exceptional points, at which two eigenstates coalesce, have been observed in complex scattering systems.

Developments in computer science could allow astrophysicists to reverse the cosmic distribution of matter from today back to any point in the Universe’s history.

Feature on:
Sebastian von Hausegger, Bruno Lévy, and Roya Mohayaee
Phys. Rev. Lett. 128, 201302 (2022)

Enhancement of the supercurrent, induced by a magnetic field in a nanowire, is caused by quasiparticle trapping rather than Majorana fermions.

A system-independent relation quantifying the energetic cost of a measurement is derived for quantum metrological protocols.

A discrepancy between different measurements of the Hubble constant could be removed by the existence of an exotic form of dark matter.

Synopsis on:
Francis-Yan Cyr-Racine, Fei Ge, and Lloyd Knox
Phys. Rev. Lett. 128, 201301 (2022)

A classical model for arbitrary systems exhibiting hysteresis is combined with machine learning techniques to efficiently create models for characterizing hysteresis in accelerator magnets and to improve model-based optimization.

Coexistence of nontrivial topology and intrinsic superconductivity is observed in few-layer stanene films on a Bi(111) substrate.

The constant for phonon-induced spin relaxation in the Elliot-Yafet mechanism is not constant, but instead decreases by one order of magnitude as the thickness of an Al film is varied from 8.5 to 300 nm.

Experiments in Dirac-cone metamaterials present the first observation of direction-independent phase matching in a medium where phase matching is relevant for parametric nonlinear optical processes.

A water wave incident on a grooved wall is shown to be analogous to electromagnetic waves called surface plasmon polaritons.

Synopsis on:
Linkang Han, Shiming Chen, and Huanyang Chen
Phys. Rev. Lett. 128, 204501 (2022)

Experiments and simulations explain the unusual nature of the structure’s springiness.

Focus story on:
Yashraj Bhosale et al.
Phys. Rev. Lett. 128, 198003 (2022)

Robert Garisto (right) has been named the Managing Editor of Physical Review Letters, the world’s premier physics journal. As Managing Editor, Garisto will lead PRL’s editorial team and provide scientific direction for the journal in partnership with PRL’s Lead Editor, Hugues Chaté.

APS Editor in Chief, Michael Thoennessen, discusses a new opportunity for communicating authors to include their pronouns together with their contact email in order to promote a more respectful, inclusive, and equitable environment.