Suppressing deleterious effects of spontaneous emission in creating bound states in cold atom continuum

Naskar, Somnath; Sardar, Dibyendu; Deb, Bimalendu; Agarwal, G. S.

doi:10.1088/1361-6455/ab4ef2

Cited by 4 publications

(3 citation statements)

References 51 publications

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“…Normally, the spontaneous emission rate of atoms is proportional to the scattering rate, so the big peaks should be avoided when choosing frequency shifts. The spontaneous emission rate will affect the atomic temperature and the experimental results [27,28]. In addition, the Raman transition rate is also very high at the peak of the scattering rate in Figure 2b.…”

Section: Theoretical Analysis Of the Cooling Caused By The Laser Systemmentioning

confidence: 94%

A Simplified Laser System for Atom Interferometry Based on a Free-Space EOM

Zhao

Cheng

et al. 2022

Photonics

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In this paper, a compact laser system for 87Rb atom interferometry based on only one free-space electro-optic modulator (EOM) was realized, where repumping and Raman beams were generated with a free-space EOM. In addition, this laser system does not require a laser amplifier compared to fibered EOM since fibered EOM cannot transmit high-power lasers. However, due to the narrow modulation linewidth of free-space EOM, it is impossible to obtain the frequencies of repumping and Raman beams separately, which would lead to some complicated effects. Therefore, a theoretical analysis was carried out to solve this problem, and a new frequency scheme for AI is proposed. For the experiment, the laser system of AI was built up. Moreover, the atomic interference fringes were obtained with a contrast of 20.7% (T = 60 ms) and the fitted phase resolution is approximately 1.25 mrad. The presented laser system could provide a new solution for compact AI systems in the future.

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Section: Theoretical Analysis Of the Cooling Caused By The Laser Systemmentioning

confidence: 94%

A Simplified Laser System for Atom Interferometry Based on a Free-Space EOM

Zhao

Cheng

et al. 2022

Photonics

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“…Such a resonance is also called the bound state in the continuum, which has been observed in various systems such as quantum billiard and quantum dot [39,40]. The bound state in the continuum can be prepared by lasers near a magnetic Feshbach resonance in ultracold atoms but decays fast due to the spontaneous emission loss [41,42].…”

Section: Introductionmentioning

confidence: 99%

The two-body collision controlled by the magnetic field and laser field near magnetic Feshbach resonance

Lyu

et al. 2023

Front. Phys.

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It is crucial to control the collision between ultracold atoms by applying external fields. We developed a theoretical model for investigating the s-wave scattering of ultracold atoms controlled by the magnetic field and laser field. The calculation is performed by using the close-coupling method and mapped Fourier grid method. Due to the interference between the photoassociation and bound-to-bound transitions, the bound state in the continuum, which is a resonance with a vanishing width, occurs at the magnetic field position near the magnetic Feshbach resonance. The widths of resonances in the neighborhood of the bound state in the continuum are narrow. Changing the laser intensity can shift the magnetic field position where the bound state in the continuum occurs through modifying the ground molecular state to induce wide resonances at desired magnetic field positions. By increasing the resonance width, the tunability of the real part of the scattering length at resonances can be significantly improved. Changing the laser intensity can also adjust the coupling between the ground and excited molecular states. When the coupling between the ground and excited molecular states approaches zero, a resonance is induced, and the photoassociation and bound-to-bound transitions are both significantly suppressed at this resonance. Therefore, the atomic loss peak due to spontaneous emission does not appear at this resonance. The magnetic field position of this resonance is stable against the change in laser frequency.

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“…In recent years, considerable efforts have been devoted to non-Hermitian systems which have intriguing features and applications [38][39][40][41][42]. In general, a proper description of a real physical system requires a non-Hermitian Hamiltonian [42][43][44][45][46][47]. Controlled gain and loss or environmentinduced dissipations can be harnessed to engineer an effective non-Hermitian Hamiltonian, which has been experimentally realized in atomic, optical, and optomechanical systems [48][49][50][51][52][53][54][55].…”

Section: Introductionmentioning

confidence: 99%

Protected quantum coherence by gain and loss in a noisy quantum kicked rotor

Wang¹,

Zhao²

2021

J. Phys.: Condens. Matter

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We study the effects of non-Hermiticity on quantum coherence via a noisy quantum kicked rotor (NQKR). The random noise comes from the fluctuations in kick amplitude at each time. The non-Hermitian driving indicates the imaginary kicking potential, representing the environment-induced atom gain and loss. In the absence of gain and loss, the random noise destroys quantum coherence manifesting dynamical localization, which leads to classical diffusion. Interestingly, in the presence of non-Hermitian kicking potential, the occurrence of dynamical localization is highly sensitive to the gain and loss, manifesting the restoration of quantum coherence. Using the inverse participation ratio arguments, we numerically obtain a phase diagram of the classical diffusion and dynamical localization on the parameter plane of noise amplitude and non-Hermitian driving strength. With the help of analysis on the corresponding quasieigenstates, we achieve insight into dynamical localization, and uncover that the origin of the localization is interference between multiple quasi-eigenstates of the quantum kicked rotor. We further propose an experimental scheme to realize the NQKR in a dissipative cold atomic gas, which paves the way for future experimental investigation of an NQKR and its anomalous non-Hermitian properties.

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Suppressing deleterious effects of spontaneous emission in creating bound states in cold atom continuum

Cited by 4 publications

References 51 publications

A Simplified Laser System for Atom Interferometry Based on a Free-Space EOM

A Simplified Laser System for Atom Interferometry Based on a Free-Space EOM

The two-body collision controlled by the magnetic field and laser field near magnetic Feshbach resonance

Protected quantum coherence by gain and loss in a noisy quantum kicked rotor

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