Science
Physics and the wider sciences — research, discoveries and the ideas behind them.
Precessing magnetic particles as ac magnetic field sensors
Researchers have developed a new sensor that can detect weak electromagnetic waves down to the femtotesla level by exploiting the precession of a levitated magnetic particle in a vacuum. This sensor offers a large dynamic range, continuous tunability over many gigahertz, and sub-hertz frequency resolution. It can also relatively easily determine the direction of arrival of incoming electromagnetic waves.
Investigating nonlinear dynamics in a mass-spring oscillator using real-time computer vision
A low-cost laboratory system uses a smartphone camera and real-time computer vision to track the motion of a vertical mass-spring oscillator. This system allows for the investigation of damped oscillations, period measurements, spectral analysis, and phase-space reconstruction. It also enables the study of nonlinear phenomena such as harmonic generation and energy exchange between coupled oscillation modes, making advanced topics accessible in undergraduate laboratories.
Large CISS Polarization from the Hierarchy Between Transport and Geometrical Spin Currents
Researchers are re-examining the chiral-induced spin selectivity (CISS) phenomenon, which shows unexpectedly large spin polarization in chiral molecular systems. They propose that a hierarchy between geometrical spin currents and transport currents explains this, suggesting that transport acts as a weak leakage from pre-existing curved spin-current states. This model could account for the high CISS polarization observed experimentally.
A Solar-System Window for Hidden Stellar Companions
This research explores the possibility of a hidden stellar or substellar companion to the Sun, located at hundreds or thousands of astronomical units, which would be electromagnetically dark but detectable through gravity. The study constructs a mass-distance map using existing planetary constraints and suggests that such an object would need to be a gravitationally bound structure rather than a typical dark matter halo draw. It proposes that a hidden-sector star, bright in dark photons, could fit within the allowed mass and distance window, offering a benchmark for future investigations.
Positron-Emitting and Electron-Capturing Double-Beta Processes in the Standard Model and Beyond
This research paper investigates positron-emitting and electron-capturing double-beta-decay modes as complementary probes to traditional double beta decay. It analyzes candidate isotopes like ${}^{78}$Kr, ${}^{106}$Cd, and ${}^{124}$Xe, providing nuclear matrix elements and phase-space factors for both neutrinoful and neutrinoless modes. The study also interprets projected sensitivities for neutrinoless channels in terms of SMEFT operators, indicating sensitivity to lepton-number-violating new-physics scales.
Short-Duration Gamma-ray Burst and Afterglow Rates in the Rubin and Roman Era
This article discusses arXivLabs, a framework for developing and sharing new arXiv features. It highlights the project's commitment to values like openness, community, excellence, and user data privacy, and invites collaborators to contribute.