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Title: Neutral Larkin-Ovchinnikov-Fulde-Ferrell State and Chromomagnetic Instability in Two-Flavor Dense QCD

Abstract

In two-flavor dense quark matter, we describe the dynamics in the single plane wave Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) state satisfying the color and electric neutrality conditions. We find that because the neutral LOFF state itself suffers from a chromomagnetic instability in the whole region where it coexists with the (gapped or gapless) two-flavor superconducting phases, it cannot cure this instability in those phases. This is unlike the recently revealed gluonic phase which seems to be able to resolve this problem.

Authors:
; ;  [1]
  1. Department of Applied Mathematics, University of Western Ontario, London, Ontario N6A 5B7 (Canada)
Publication Date:
OSTI Identifier:
20775038
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 96; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevLett.96.022005; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; COLOR MODEL; FLAVOR MODEL; INSTABILITY; QUANTUM CHROMODYNAMICS; QUARK MATTER

Citation Formats

Gorbar, E.V., Hashimoto, Michio, and Miransky, V.A. Neutral Larkin-Ovchinnikov-Fulde-Ferrell State and Chromomagnetic Instability in Two-Flavor Dense QCD. United States: N. p., 2006. Web. doi:10.1103/PhysRevLett.96.022005.
Gorbar, E.V., Hashimoto, Michio, & Miransky, V.A. Neutral Larkin-Ovchinnikov-Fulde-Ferrell State and Chromomagnetic Instability in Two-Flavor Dense QCD. United States. doi:10.1103/PhysRevLett.96.022005.
Gorbar, E.V., Hashimoto, Michio, and Miransky, V.A. Fri . "Neutral Larkin-Ovchinnikov-Fulde-Ferrell State and Chromomagnetic Instability in Two-Flavor Dense QCD". United States. doi:10.1103/PhysRevLett.96.022005.
@article{osti_20775038,
title = {Neutral Larkin-Ovchinnikov-Fulde-Ferrell State and Chromomagnetic Instability in Two-Flavor Dense QCD},
author = {Gorbar, E.V. and Hashimoto, Michio and Miransky, V.A.},
abstractNote = {In two-flavor dense quark matter, we describe the dynamics in the single plane wave Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) state satisfying the color and electric neutrality conditions. We find that because the neutral LOFF state itself suffers from a chromomagnetic instability in the whole region where it coexists with the (gapped or gapless) two-flavor superconducting phases, it cannot cure this instability in those phases. This is unlike the recently revealed gluonic phase which seems to be able to resolve this problem.},
doi = {10.1103/PhysRevLett.96.022005},
journal = {Physical Review Letters},
number = 2,
volume = 96,
place = {United States},
year = {Fri Jan 20 00:00:00 EST 2006},
month = {Fri Jan 20 00:00:00 EST 2006}
}
  • We present a summary of the recent advances achieved in the study of three flavor Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) phase of QCD. We have explored, using a Ginzburg-Landau expansion of the free energy, the LOFF phase with three flavors, in the simplest single plane wave structure, using the NJL four-fermion coupling. We have found that this phase does not suffer the chromo-magnetic instability problem. Moreover a preliminary study of astrophysical effects of quark matter in the aforementioned phase has been done and we have evaluated self-consistently the strange quark mass extending the pairing ansatz to the CubeX and 2Cube45z structure. Finally wemore » have investigated the possibility of Goldstone bosons condensation in the favored cubic structures of LOFF phase.« less
  • We explore the phase structure of two-color and two-flavor QCD in the space of the quark chemical potential {mu}{sub q} and the isospin chemical potential {mu}{sub I}. Using a mean-field model we calculate the chiral and diquark condensates, {sigma} and {delta}, self-consistently. In weak coupling and in the chiral limit, we confirm the interval of the isospin chemical potential, 0.71{delta}{sub 0}<{mu}{sub I}<0.75{delta}{sub 0}, in which a single plane-wave Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) phase is favored over isotropic superfluidity and normal quark matter. The LOFF window becomes slightly wider at high density. For stronger coupling with nonzero quark mass, which is relevant tomore » currently available numerical simulations in lattice two-color QCD, the single plane-wave LOFF phase appears only at sufficiently high density. The prediction obtained for the LOFF region could be tested with lattice since we can prove that the present system is free from the fermion sign problem. We draw the energy landscape on which local minima corresponding to the isotropic superfluid phase and the LOFF phase and a local maximum corresponding to the gapless phase are manifest. Our results clearly illustrate the path from the unstable gapless phase down to the LOFF phase.« less
  • A rotating ultracold S-wave superfluid Fermi gas is studied when the mismatch in chemical potentials {delta}{mu} (and the population imbalance {delta}n) corresponds to the Larkin-Ovchinnikov-Fulde-Ferrell state in the vicinity of the Lifshitz critical point. It is shown that under these conditions the critical angular velocity {omega}{sub c2} in two-dimensional systems is an oscillating function of temperature and {delta}n giving rise to reentrant superfluid phases. The reason for this behavior is the population by Cooper pairs of the Landau levels (n{>=}1) above the lowest one (n=0)
  • We discuss possible destinations from the chromomagnetic instability in color superconductors with Fermi surface mismatch {delta}{mu}. In the two-flavor superconducting (2SC) phase we calculate the effective potential for color vector potentials A{sub {alpha}} which are interpreted as the net momenta q of pairing in the Larkin-Ovchinnikov-Fulde-Ferrel (LOFF) phase. When 1/{radical}(2)<{delta}{mu}/{delta}<1 where {delta} is the gap energy, the effective potential suggests that the instability leads to a LOFF-like state which is characterized by color-rotated phase oscillations with small q. In the vicinity of {delta}{mu}/{delta}=1/{radical}(2) the magnitude of q continuously increases from zero as the effective potential has negative larger curvature atmore » vanishing A{sub {alpha}} that is the Meissner mass squared. In the gapless 2SC (g2SC) phase, in contrast, the effective potential has a minimum at gA{sub {alpha}}{approx}{delta}{mu}{approx}{delta} even when the negative Meissner mass squared is infinitesimally small. Our results imply that the chromomagnetic instability found in the gapless phase drives the system toward the LOFF state with q{approx}{delta}{mu}.« less
  • We report upper critical-field measurements in the metal-free-all-organic superconductor {beta}{double_prime}-(ET){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3} obtained from measuring the in-plane penetration depth using the tunnel diode oscillator technique. For magnetic field applied parallel to the conducting planes the low-temperature upper critical fields are found to exceed the Pauli limiting field calculated by using a semiempirical method. Furthermore, we found a signature that could be the phase transition between the superconducting vortex state and the Fulde-Ferrell-Larkin-Ovchinnikov state in the form of a kink just below the upper critical field and only at temperatures below 1.23 K.