Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 1709.04531

Negative-mass instability of the spin and motion of an atomic gas driven by optical cavity backaction

Jonathan Kohler·Justin A. Gerber·Emma Dowd·Dan M. Stamper-Kurn
View original source ↗Read source document ↗Export metadata ↓

Abstract

We realize a spin-orbit interaction between the collective spin precession and center-of-mass motion of a trapped ultracold atomic gas, mediated by spin- and position-dependent dispersive coupling to a driven optical cavity. The collective spin, precessing near its highest-energy state in an applied magnetic field, can be approximated as a negative-mass harmonic oscillator. When the Larmor precession and mechanical motion are nearly resonant, cavity mediated coupling leads to a negative-mass instability, driving exponential growth of a correlated mode of the hybrid system. We observe this growth imprinted on modulations of the cavity field and estimate the full covariance of the resulting two-mode state by observing its transient decay during subsequent free evolution.

Explore related subjects

physics.atom-phcond-mat.quant-gasquant-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Jonathan Kohler, Justin A. Gerber, Emma Dowd, Dan M. Stamper-Kurn. 2018-01-02. Negative-mass instability of the spin and motion of an atomic gas driven by optical cavity backaction. https://doi.org/10.1103/physrevlett.120.013601

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Momentum-space signatures of radial orbital nodes in XUV photoionization

Photoelectron momentum distributions (PMDs) are widely used to probe light matter interactions, yet their angular features are generally assumed to be governed primarily by angular momentum selection rules. We show that the radial structure of the initial bound orbital can qualitatively modify PMD tilt beyond these con- ventional expectations. Using ab-initio time dependent Schrödinger equation calculations, we demonstrate this through comparative studies of single-photon XUV ionization in neon and argon. While neon exhibits a smooth, monotonic increase in PMD tilt with wavelength, argon shows pronounced suppression and reversal near the wavelength where the d wave dipole matrix element passes through a minimum. A partial wave analysis reveals that this non monotonic behaviour originates from a radial node induced minimum in the d wave dipole matrix element, producing a rapid phase jump between interfering s and d wave ionization channels. We further show that atomic interferometric circular dichroism (AICD) provides a sensitive, experimentally accessible probe of this effect.

physics.atom-ph↗
arXiv2026

Extreme-ultraviolet spectroscopy using quantum logic: a feasibility study for the 1S-2S transition in singly-ionized helium

Extreme-ultraviolet (XUV) spectroscopy represents an important new direction in precision physics, with potential applications ranging from the metrology of fundamental constants to tests of physics beyond the Standard Model. However, the application of quantum control methods for precision spectroscopy remains an open challenge in the XUV range. Here we present a novel quantum logic (QL) spectroscopy method for precision spectroscopy of weak XUV transitions, and numerically validate its feasibility for the $1S-2S$ transition at 40.81\,eV in singly-ionized helium (He$^{+}$). We propose a scheme based on a single He$^{+}$ ion co-trapped with a Be$^{+}$ ion in a Paul trap, and He$^{+}$ excitation with pairs of frequency-comb (FC) laser pulses upconverted to the XUV via High-Harmonic Generation (HHG). We investigate a nondestructive QL scheme to detect $1S-2S$ excitation, and compare its performance with a destructive readout based on state-selective ionization. Phase coherence of the XUV light is modelled and an optical cavity is used to filter the FC pulses prior to HHG. We model the motional excitation dynamics of trapped ions outside the Lamb-Dicke regime, and numerically validate a scheme we proposed in \cite{Grundeman} to cancel the first-order Doppler broadening and the recoil shift by synchronizing the ion's secular period with the time delay between the two excitation pulses. We show that precision spectroscopy of the $1S-2S$ transition in He$^{+}$ at the 10 kHz level is feasible, for improved tests of quantum electrodynamics (QED), a measurement of the Rydberg constant $R_{\infty}$ independent of hydrogen measurements, or an improved determination of the alpha particle and helion charge radii. The proposed method may also be applied to XUV spectroscopy of other ions outside the Lamb-Dicke regime.

physics.atom-ph↗
arXiv2026

Second-Order Rayleigh-Schrödinger Perturbation Theory for the Grasp

A developed method, based on the stationary second-order Rayleigh-Schrödinger many-body perturbation theory in an irreducible tensorial form, allows us to determine the most important core-valence, core, core-core, and valence-valence correlations for any atom or ion with an arbitrary number of valence and core electrons. This paper presents the Feynman diagrams that describe these correlations. Additionally, it provides the rules for obtaining algebraic expressions in an irreducible tensorial form for any Feynman diagram coming from second-order many-body perturbation theory. Whereas some types of the valence-valence and core-valence correlations are described by the three-particle Feynman diagrams, additional developments to calculate the spin-angular parts of these diagrams have been made to the program library librang of the Grasp2018. As an example of the application of the developed method, the atomic calculations of the energy level structure and transition data for Ar II are presented.

physics.atom-ph↗