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

verfasst von: Jan Kiethe, Lars Timm, Haggai Landa, Dimitri Kalincev, Giovanna Morigi, Tanja E. Mehlstäubler
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.
Organisationseinheit(en): Institut für Theoretische Physik
Institut für Quantenoptik
QuantumFrontiers
SFB 1227: Designte Quantenzustände der Materie (DQ-mat)
Externe Organisation(en): Physikalisch-Technische Bundesanstalt (PTB)
Universität Paris-Saclay
University of Haifa
Universität des Saarlandes
Typ: Artikel
Journal: Physical Review B
Band: 103
ISSN: 2469-9950
Publikationsdatum: 19.03.2021
Publikationsstatus: Veröffentlicht
Peer-reviewed: Ja
ASJC Scopus Sachgebiete: Elektronische, optische und magnetische Materialien, Physik der kondensierten Materie
Elektronische Version(en): https://doi.org/10.1103/PhysRevB.103.104106 (Zugang: Offen)

BibTeX

@article{c9dc893e0e7c45d1ba5dbee09a72d2bd,
title = "Finite-temperature spectrum at the symmetry-breaking linear to zigzag transition",
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.",
author = "Jan Kiethe and Lars Timm and Haggai Landa and Dimitri Kalincev and Giovanna Morigi and Mehlst{\"a}ubler, {Tanja E.}",
note = "Funding Information: We gratefully thank J. Keller for fruitful discussions. This project has been funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) through Grant No. CRC 1227 (DQ-mat, project A07) and under Germanys Excellence Strategy EXC-2123 QuantumFrontiers 390837967. This project 17FUN07 CC4C has received funding from the EMPIR programme co-financed by the Participating States and from the European Union's Horizon 2020 research and innovation programme. G.M. acknowledges support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) through Grant No. CRC TRR 306 QuCoLiMa (“Quantum Cooperativity of Light and Matter”) and by the German Ministry of Education and Research (BMBF) via the QuantERA project NAQUAS. Project NAQUAS has received funding from the QuantERA ERA-NET Cofund in Quantum Technologies implemented within the European Union's Horizon2020 program.",
year = "2021",
month = mar,
day = "19",
doi = "10.1103/PhysRevB.103.104106",
language = "English",
volume = "103",
journal = "Physical Review B",
issn = "2469-9950",
publisher = "American Institute of Physics",
number = "10",
}