Spectroscopy of collective modes in a Bose-Einstein condensate: From single to double excitation periods

Fuente: arXiv
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Autori principali: Machado, Leandro A., Madeira, Lucas, Caracanhas, Mônica A., Bagnato, Vanderlei S.
Natura: Preprint
Pubblicazione: 2024
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author Machado, Leandro A.
Madeira, Lucas
Caracanhas, Mônica A.
Bagnato, Vanderlei S.
author_facet Machado, Leandro A.
Madeira, Lucas
Caracanhas, Mônica A.
Bagnato, Vanderlei S.
contents Collective modes are coherent excitations in Bose-Einstein condensates (BECs), and their study provides insight into the macroscopic quantum phenomena that govern these systems. Collective mode frequencies can be used to probe the properties of BECs, such as the trap geometry, the interatomic interactions, and the presence of defects; hence, it is essential to develop methods for high-resolution determination of collective mode frequencies. A standard technique consists of a single pulse of an external oscillatory field, which we denote Rabi-like due to the analogy with the field of nuclear magnetic resonances. In this work, we propose a method to achieve a better resolution than the Rabi-like protocol, which consists of two oscillating fields separated in time, which we call Ramsey-like. We focus on BECs in harmonic traps, considering mainly the quadrupole and breathing modes for different trap anisotropy values and comparing the results using single and double excitation zones. First, we employ a variational approach with a Thomas-Fermi ansatz, which gives rise to dynamical equations that are numerically solved. Then, we modeled the problem as a three-level system, offering a concise and alternative description of the same dynamics, enabling the idea of coherent control of these collective modes. Both approaches show that the Ramsey-like protocol provides a better resolution than the Rabi-like. This offers the possibility of measuring collective mode frequencies with higher precision, which is important in experiments where they are used as indirect measurements of properties that are difficult to probe.
format Preprint
id arxiv_https___arxiv_org_abs_2411_03939
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Spectroscopy of collective modes in a Bose-Einstein condensate: From single to double excitation periods
Machado, Leandro A.
Madeira, Lucas
Caracanhas, Mônica A.
Bagnato, Vanderlei S.
Quantum Gases
Quantum Physics
Collective modes are coherent excitations in Bose-Einstein condensates (BECs), and their study provides insight into the macroscopic quantum phenomena that govern these systems. Collective mode frequencies can be used to probe the properties of BECs, such as the trap geometry, the interatomic interactions, and the presence of defects; hence, it is essential to develop methods for high-resolution determination of collective mode frequencies. A standard technique consists of a single pulse of an external oscillatory field, which we denote Rabi-like due to the analogy with the field of nuclear magnetic resonances. In this work, we propose a method to achieve a better resolution than the Rabi-like protocol, which consists of two oscillating fields separated in time, which we call Ramsey-like. We focus on BECs in harmonic traps, considering mainly the quadrupole and breathing modes for different trap anisotropy values and comparing the results using single and double excitation zones. First, we employ a variational approach with a Thomas-Fermi ansatz, which gives rise to dynamical equations that are numerically solved. Then, we modeled the problem as a three-level system, offering a concise and alternative description of the same dynamics, enabling the idea of coherent control of these collective modes. Both approaches show that the Ramsey-like protocol provides a better resolution than the Rabi-like. This offers the possibility of measuring collective mode frequencies with higher precision, which is important in experiments where they are used as indirect measurements of properties that are difficult to probe.
title Spectroscopy of collective modes in a Bose-Einstein condensate: From single to double excitation periods
topic Quantum Gases
Quantum Physics
url https://arxiv.org/abs/2411.03939