Finite-temperature spectrum at the symmetry-breaking linear to zigzag transition

Kiethe J, Timm L, Landa H, Kalincev D, Morigi G, Mehlstäubler T (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Physical Review B American Physical Society

Book Volume: 103

Article Number: 104106

Journal Issue: 10

DOI: 10.1103/PhysRevB.103.104106

Abstract

We investigate the normal-mode spectrum of a trapped ion chain at the symmetry-breaking linear to zigzag transition and at finite temperatures. For this purpose, we modulate the amplitude of the Doppler cooling laser to excite and measure mode oscillations. The expected mode softening at the critical point, a signature of the second-order transition, is not observed. Numerical simulations show that this is mainly due to the finite temperature of the chain. Inspection of the trajectories suggest that the thermal shifts of the normal-mode spectrum can be understood by the ions collectively jumping between the two ground-state configurations of the symmetry-broken phase. We develop an effective analytical model, which allows us to reproduce the low-frequency spectrum as a function of the temperature and close to the transition point. In this model, the frequency shift of the soft mode is due to the anharmonic coupling with the high-frequency modes of the spectrum, acting as an averaged effective thermal environment. Our study could prove important for implementing ground-state laser cooling close to the critical point.

Additional Organisation(s)

Sonderforschungsbereich/Transregio 306/1: Quantenkooperativität von Licht und Materie - QuCoLiMa

Related research project(s)

Collective quantum dynamics of structural- and spin-defects in ion crystals (B01) TRR 306: Quantenkooperativität von Licht und Materie – QuCoLiMa Jan. 1, 2021 - Dec. 31, 2024

Involved external institutions

Universität des Saarlandes (UdS) DE Germany (DE) Gottfried Wilhelm Leibniz Universität Hannover DE Germany (DE) Physikalisch-Technische Bundesanstalt (PTB) DE Germany (DE) Université Paris-Saclay FR France (FR)

How to cite

APA:

Kiethe, J., Timm, L., Landa, H., Kalincev, D., Morigi, G., & Mehlstäubler, T. (2021). Finite-temperature spectrum at the symmetry-breaking linear to zigzag transition. Physical Review B, 103(10). https://dx.doi.org/10.1103/PhysRevB.103.104106

MLA:

Kiethe, Jan, et al. "Finite-temperature spectrum at the symmetry-breaking linear to zigzag transition." Physical Review B 103.10 (2021).

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