Nonlinear dynamical response of interacting bosons to synthetic electric field

Year: 2020

Authors: Roy A., Bera S., Saha K.

Autors Affiliation: Univ Trento, INO CNR BEC Ctr, I-38123 Trento, Italy; Univ Trento, Dipartimento Fis, I-38123 Trento, Italy; Max Planck Inst Phys Komplexer Syst, Nothnitzer Str 38, D-01187 Dresden, Germany; Indian Inst Technol, Dept Phys, Mumbai 400076, Maharashtra, India; Natl Inst Sci Educ & Res, Sch Phys Sci, Jatni 752050, Odisha, India; Homi Bhabha Natl Inst, Training Sch Complex, Mumbai 400094, Maharashtra, India.

Abstract: We theoretically study the nonlinear response of interacting neutral bosonic gas in a synthetically driven one-dimensional optical lattice. In particular, we examine the bosonic analog of electronic higher harmonic generation in a strong time-dependent synthetic vector potential manifesting itself as the synthetic electric field. We show that the vector potential can generate reasonably high harmonics in the insulating regime, while the superfluid regime exhibits only a few harmonics. In the insulating regime, the number of harmonics increases with the increase in the strength of the vector potential. This originates primarily due to the field-driven resonant and nonresonant excitations in the neutral Mott state and their recombination with the ground state. If the repulsive interaction between two atoms (U) is close to the strength of the gauge potential (A(0)), the resonant quasiparticle-quasihole pairs on nearest-neighbor sites, namely, dipole states, are found to a play a dominant role in generating higher harmonics. However, in the strong-field limit A(0) >= U, the nonresonant states where quasiparticle-quasihole pairs are not on nearest-neighbor sites give rise to higher harmonics.

Journal/Review: PHYSICAL REVIEW RESEARCH

Volume: 2 (4)      Pages from: 43133-1  to: 43133-8

More Information: A.R. acknowledges support from Provincia Autonoma di Trento. S.B. would like to thank G. Dixit, F. Evers, and S. Pujari for several discussions. S.B. acknowledges support from Department of Science and Technology, India, through Ramanujan Fellowship Grant No. SB/S2/RJN-128/2016 and through Early Career Award No. ECR/2018/000876, and MPG for funding through the Max Planck Partner Group at IITB. We thank the visitor program of Max Planck Institute for the Physics of Complex Systems, Dresden, for hospitality during the initial stages of the work. We also thank the anonymous referees for their thorough review and valuable comments, which contributed to improving the quality of the manuscript.
KeyWords: High-harmonic Generation; Atoms; Superfluid; Insulator; 1064-nm
DOI: 10.1103/PhysRevResearch.2.043133

Citations: 6
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