Coherence and spectral weight transfer in the dynamic structure factor of cold lattice bosons

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• 作者：T.A. Zaleski ; ^{t.zaleski@int.pan.wroc.pl" class="auth_mail" title="E-mail the corresponding author} ; T.K. Kopeć
• 关键词：Bose-Einstein condensation ; Ultracold atoms in optical lattice ; Dynamic structure factor ; Bose-Hubbard model
• 刊名：Physica B: Physics of Condensed Matter
• 出版年：2017
• 出版时间：1 January 2017
• 年：2017
• 卷：504
• 期：Complete
• 页码：74-79
• 全文大小：796 K

文摘

Ultracold atoms have been used to create novel correlated quantum phases allowing to address many solid-state physics problems using the quasi-particle concept, which is the foundation of our understanding of many-body quantum systems. For bosons, the simplest kinds of excited states involve two particles and they are connected to the dynamic structure factor pan id="mmlsi0018" class="mathmlsrc">pan class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0921452616304744&_mathId=si0018.gif&_user=111111111&_pii=S0921452616304744&_rdoc=1&_issn=09214526&md5=84ce7962d5ea3c793c297babed1db145" title="Click to view the MathML source">S(k,ω)pan>pan class="mathContainer hidden">pan class="mathCode">$S(\mathbf{k},\omega )$pan>pan>pan>, measured using Bragg spectroscopy, similarly to the angle-resolved photoemission spectroscopy (ARPES) in solid state physics – a major tool in the study of high-T_c cuprates. Calculation of pan id="mmlsi0019" class="mathmlsrc">pan class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0921452616304744&_mathId=si0019.gif&_user=111111111&_pii=S0921452616304744&_rdoc=1&_issn=09214526&md5=beb5bcb3865593b512c4b2c1bc10af31" title="Click to view the MathML source">S(k,ω)pan>pan class="mathContainer hidden">pan class="mathCode">$S\left(\mathbf{k},\omega \right)$pan>pan>pan> requires a significant numerical effort to determine multidimensional convolutions of momentum and frequency dependent constituents functions, which we achieve using parallelized fast Fourier transform. As a result, we are able to show that spectral weight transfer between low and high energies is an intrinsic property of the strongly correlated Bose system in close analogy to the doped Mott-Hubbard electronic insulator. Furthermore, the appearance of sharp coherence peaks in the superfluid phase of the cold bosons closely resembles the formation of sharply defined quasiparticle excitations below T_c in cuprates suggesting an intimate connection between the intrinsic nature of these seemingly different systems.