Quasi-Nambu-Goldstone Modes in Bose-Einstein Condensates

Uchino, Shun; Kobayashi, Michikazu; Nitta, Muneto; Ueda, Masahito

doi:10.1103/physrevlett.105.230406

Cited by 58 publications

(52 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The present study has shed light on the pivotal role of quantum fluctuations in the first-order quantum phase transitions. With the importance of the effect of quantum fluctuations shown above, it is worth investigating the implication of this study to closely related problems such as the Coleman-Weinberg mechanism of quantum symmetry breaking [48], quantum anomaly [49], and quasi-Nambu-Goldstone modes [50]. It would also be of interest to study the dynamics of the first-order quantum phase transitions without metastability since criticality might arise from the flat energy landscape at the phase boundary.…”

Section: Discussionmentioning

confidence: 98%

Fluctuation-induced and symmetry-prohibited metastabilities in spinor Bose-Einstein condensates

2013

Self Cite

View full text Add to dashboard Cite

Spinor Bose-Einstein condensates provide a unique example in which the Bogoliubov theory fails to describe the metastability associated with first-order quantum phase transitions. This problem is resolved by developing the spinor Beliaev theory which takes account of quantum fluctuations of the condensate. It is these fluctuations that generate terms of higher than the fourth order in the order-parameter field which are needed for the first-order phase transitions. Besides the conventional first-order phase transitions which are accompanied by metastable states, we find a class of first-order phase transitions which are not accompanied by metastable states. The absence of metastability in these phase transitions holds to all orders of approximation since the metastability is prohibited by the symmetry of the Hamiltonian at the phase boundary. Finally, the possibility of macroscopic quantum tunneling from a metastable state to the ground state is discussed.

show abstract

Section: Discussionmentioning

confidence: 98%

Fluctuation-induced and symmetry-prohibited metastabilities in spinor Bose-Einstein condensates

2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…This point is also discussed in a different system, spinor Bose-Einstein condensate 28 . Nevertheless, the mass of the Leggett mode is a good indicator of inter-band frustration.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, the massless behavior in region III is related to a degeneracy. The occurrence of such an exotic massless mode and a degeneracy between ground states were pointed out by several authors [27][28][29][30] . A symmetry analysis of Eq.…”

Section: Mass Reduction Of a Leggett Mode By Inter-band Frustrationmentioning

confidence: 99%

Massless collective excitations in frustrated multiband superconductors

Kobayashi¹,

Machida²,

Ota³

et al. 2013

Phys. Rev. B

View full text Add to dashboard Cite

We study collective excitations in three-and four-band superconductors with inter-band frustration, which causes neither 0 nor π inter-band phases in the superconducting state. Using a low-energy spin-Hamiltonian originating from a multi-band tight-binding model, we find that mass reduction of a Leggett mode occurs in a wide parameter region of this four-band system. As a limitting case, we have a massless Leggett mode. This massless mode is related to the fact that the mean-field energy does not depend on a relative phase of superconducting order parameters. In other words, we find a link of the massless mode with a degeneracy between a time-reversalsymmetry-breaking state (neither 0 nor π phases) and a time-reversal-symmetric state (either 0 or π phases). Therefore, the mass of collective modes characterizes well the time-reversal symmetry in frustrated multi-band superconductors.

show abstract

“…[4], were performed using scalar BECs, BECs with internal degrees of freedom (spinor BECs [14,15]) confined in simply connected geometries have also been realized experimentally [16,17], In spinor BECs, there exist various topological defects [18][19][20][21][22][23][24][25][26][27][28], spin textures [29][30][31][32][33], and Nambu-Goldstone modes (NGMs) [34][35][36][37][38][39] due to their spontaneous symmetry breaking.…”

Section: Introductionmentioning

confidence: 99%

Metastable spin textures and Nambu-Goldstone modes of a ferromagnetic spin-1 Bose-Einstein condensate confined in a ring trap

Kunimi

2014

Phys. Rev. A

View full text Add to dashboard Cite

We investigate the metastability of a ferromagnetic spin-1 Bose-Einstein condensate conhned in a quasi-onedimensional rotating ring trap by solving the spin-1 Gross-Pitaevskii equation. We find analytical solutions that exhibit spin textures. By performing linear stability analysis, it is shown that the solutions can become metastable states. We also find that the number of Nambu-Goldstone modes changes at a certain rotation velocity without changing the continuous symmetry of the order parameter.

show abstract

Quasi-Nambu-Goldstone Modes in Bose-Einstein Condensates

Cited by 58 publications

References 16 publications

Fluctuation-induced and symmetry-prohibited metastabilities in spinor Bose-Einstein condensates

Fluctuation-induced and symmetry-prohibited metastabilities in spinor Bose-Einstein condensates

Massless collective excitations in frustrated multiband superconductors

Metastable spin textures and Nambu-Goldstone modes of a ferromagnetic spin-1 Bose-Einstein condensate confined in a ring trap

Contact Info

Product

Resources

About