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Title: Collective phenomena in a quasi-two-dimensional system of fermionic polar molecules: Band renormalization and excitons

Abstract

We theoretically analyze a quasi-two-dimensional system of fermionic polar molecules trapped in a harmonic transverse confining potential. The renormalized energy bands are calculated by solving the Hartree-Fock equation numerically for various trap and dipolar interaction strengths. The intersubband excitations of the system are studied in the conserving time-dependent Hartree-Fock (TDHF) approximation from the perspective of lattice modulation spectroscopy experiments. We find that the excitation spectrum consists of both intersubband particle-hole excitation continua and antibound excitons whose antibinding behavior is associated to the anisotropic nature of dipolar interactions. The excitonic modes are shown to capture the majority of the spectral weight. We evaluate the intersubband transition rates in order to investigate the nature of the excitonic modes and find that they are antibound states formed from particle-hole excitations arising from several subbands. We discuss the sum rules in the context of lattice modulation spectroscopy experiments and utilize them to check the consistency of the obtained results. Our results indicate that the excitonic effects persist for interaction strengths and temperatures accessible in the current experiments with polar molecules.

Authors:
;  [1]
  1. Physics Department, Harvard University, Cambridge, Massachusetts 02138 (United States)
Publication Date:
OSTI Identifier:
22072162
Resource Type:
Journal Article
Journal Name:
Physical Review. A
Additional Journal Information:
Journal Volume: 84; Journal Issue: 3; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1050-2947
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; EXCITATION; EXCITONS; FERMIONS; HARTREE-FOCK METHOD; INTERACTIONS; MOLECULES; SPECTROSCOPY; SUM RULES; TIME DEPENDENCE; TRAPPING; TWO-DIMENSIONAL CALCULATIONS

Citation Formats

Babadi, Mehrtash, and Demler, Eugene. Collective phenomena in a quasi-two-dimensional system of fermionic polar molecules: Band renormalization and excitons. United States: N. p., 2011. Web. doi:10.1103/PHYSREVA.84.033636.
Babadi, Mehrtash, & Demler, Eugene. Collective phenomena in a quasi-two-dimensional system of fermionic polar molecules: Band renormalization and excitons. United States. doi:10.1103/PHYSREVA.84.033636.
Babadi, Mehrtash, and Demler, Eugene. Thu . "Collective phenomena in a quasi-two-dimensional system of fermionic polar molecules: Band renormalization and excitons". United States. doi:10.1103/PHYSREVA.84.033636.
@article{osti_22072162,
title = {Collective phenomena in a quasi-two-dimensional system of fermionic polar molecules: Band renormalization and excitons},
author = {Babadi, Mehrtash and Demler, Eugene},
abstractNote = {We theoretically analyze a quasi-two-dimensional system of fermionic polar molecules trapped in a harmonic transverse confining potential. The renormalized energy bands are calculated by solving the Hartree-Fock equation numerically for various trap and dipolar interaction strengths. The intersubband excitations of the system are studied in the conserving time-dependent Hartree-Fock (TDHF) approximation from the perspective of lattice modulation spectroscopy experiments. We find that the excitation spectrum consists of both intersubband particle-hole excitation continua and antibound excitons whose antibinding behavior is associated to the anisotropic nature of dipolar interactions. The excitonic modes are shown to capture the majority of the spectral weight. We evaluate the intersubband transition rates in order to investigate the nature of the excitonic modes and find that they are antibound states formed from particle-hole excitations arising from several subbands. We discuss the sum rules in the context of lattice modulation spectroscopy experiments and utilize them to check the consistency of the obtained results. Our results indicate that the excitonic effects persist for interaction strengths and temperatures accessible in the current experiments with polar molecules.},
doi = {10.1103/PHYSREVA.84.033636},
journal = {Physical Review. A},
issn = {1050-2947},
number = 3,
volume = 84,
place = {United States},
year = {2011},
month = {9}
}