79,613 research outputs found
Cooling of strange stars in the color-flavor locked phase with a rotating crust Cooling of strange stars in the color-flavor locked phase with a rotating crust
The presence of the color-flavor locked (CFL) phase strongly suppresses the
neutrino emission processes and the quark specific heat. As a result the
cooling of the strange stars in the CFL phase is dominated by deconfinement
heating and surface emission. The temperature of these stars with strong
magnetic field () rise significantly during the first several
ten or hundred years, which may be an effective signature of strange stars as
implicated by pulsar 0540-69. Furthermore a limit line is predicted, which
means compact stars have an upper limit temperature at any moment. We still may
search for the candidates for strange stars in the CFL phase along the limit
line.
The presence of the color-flavor locked (CFL) phase strongly suppresses the
neutrino emission processes and the quark specific heat. As a result the
cooling of the strange stars in the CFL phase is dominated by deconfinement
heating and surface emission. The temperature of these stars with strong
magnetic field () rise significantly during the first several
ten or hundred years, which may be an effective signature of strange stars as
implicated by pulsar 0540-69. Furthermore a limit line is predicted, which
means compact stars have an upper limit temperature at any moment. We still may
search for the candidates for strange stars in the CFL phase along the limit
line.Comment: 9 pages, 3 figures 9 pages, 3 figure
Two-hole ground state wavefunction: Non-BCS pairing in a - two-leg ladder system
Superconductivity is usually described in the framework of the
Bardeen-Cooper-Schrieffer (BCS) wavefunction, which even includes the
resonating-valence-bond (RVB) wavefunction proposed for the high-temperature
superconductivity in the cuprate. A natural question is \emph{if} any
fundamental physics could be possibly missed by applying such a scheme to
strongly correlated systems. Here we study the pairing wavefunction of two
holes injected into a Mott insulator/antiferromagnet in a two-leg ladder using
variational Monte Carlo (VMC) approach. By comparing with density matrix
renormalization group (DMRG) calculation, we show that a conventional BCS or
RVB pairing of the doped holes makes qualitatively wrong predictions and is
incompatible with the fundamental pairing force in the - model, which is
kinetic-energy-driven by nature. By contrast, a non-BCS-like wavefunction
incorporating such novel effect will result in a substantially enhanced pairing
strength and improved ground state energy as compared to the DMRG results. We
argue that the non-BCS form of such a new ground state wavefunction is
essential to describe a doped Mott antiferromagnet at finite doping.Comment: 11 pages, 5 figure
Hidden spin current in doped Mott antiferromagnets
We investigate the nature of doped Mott insulators using exact
diagonalization and density matrix renormalization group methods. Persistent
spin currents are revealed in the ground state, which are concomitant with a
nonzero total momentum or angular momentum associated with the doped hole. The
latter determines a nontrivial ground state degeneracy. By further making
superpositions of the degenerate ground states with zero or unidirectional spin
currents, we show that different patterns of spatial charge and spin
modulations will emerge. Such anomaly persists for the odd numbers of holes,
but the spin current, ground state degeneracy, and charge/spin modulations
completely disappear for even numbers of holes, with the two-hole ground state
exhibiting a d-wave symmetry. An understanding of the spin current due to a
many-body Berry-like phase and its impact on the momentum distribution of the
doped holes will be discussed.Comment: 9 pages, 9 figures, update second version including more data and
discussion adde
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