3,318 research outputs found
Ground-states of spin-1 bosons in asymmetric double-wells
In this work we investigate the different states of a system of spin-1 bosons
in two potential wells connected by tunneling, with spin-dependent interaction.
The model utilizes the well-known Bose-Hubbard Hamiltonian, adding a local
interaction term that depends on the modulus of the total spin in a well,
favoring a high- or low-spin state for different signs of the coupling
constant. We employ the concept of fidelity to detect critical values of
parameters for which the ground state undergoes significant changes. The nature
of the states is investigated through evaluation of average occupation numbers
in the wells and of spin correlations. A more detailed analysis is done for a
two-particle system, but a discussion of the three-particle case and some
results for larger numbers are also presented.Comment: 7 pages, 10 figure
Universality class of quantum criticality for strongly repulsive spin-1 bosons with antiferromagnetic spin-exchange interaction
Using the thermodynamic Bethe ansatz equations we study the quantum phase
diagram, thermodynamics and criticality of one-dimensional spin-1 bosons with
strongly repulsive density-density and antiferromagnetic spin-exchange
interactions. We analytically derive a high precision equation of state from
which the Tomonaga-Luttinger liquid physics and quantum critical behavior of
the system are computed. We obtain explicit forms for the scaling functions
near the critical points yielding the dynamical exponent and correlation
length exponent for the quantum phase transitions driven by either
the chemical potential or the magnetic field. Consequently, we further
demonstrate that quantum criticality of the system can be mapped out from the
finite temperature density and magnetization profiles of the 1D trapped gas.
Our results provide the physical origin of quantum criticality in a 1D
many-body system beyond the Tomonaga-Luttinger liquid description.Comment: 12 pages, 11 figure
Integrability and exact solution for coupled BCS systems associated with the Lie algebra
We introduce an integrable model for two coupled BCS systems through a
solution of the Yang-Baxter equation associated with the Lie algebra .
By employing the algebraic Bethe ansatz, we determine the exact solution for
the energy spectrum. An asymptotic analysis is conducted to determine the
leading terms in the ground state energy, the gap and some one point
correlation functions at zero temperature.Comment: 15 page
Seeking Environmental Stewardship One Garden at a Time
Master Gardeners and teachers in Anne Arundel County MD partnered to give hands-on educational experiences promoting environmental stewardship, how we treat the environment when nobody is watching. The partnership supports and teaches ecological reconciliation by building and caring for 4964 ft2 (1578 m2) of native plant gardens. This reproducible project encourages environmental stewardship without rhetoric, one spadeful at a time
Wilson ratio of Fermi gases in one dimension
We calculate the Wilson ratio of the one-dimensional Fermi gas with spin
imbalance. The Wilson ratio of attractively interacting fermions is solely
determined by the density stiffness and sound velocity of pairs and of excess
fermions for the two-component Tomonaga-Luttinger liquid (TLL) phase. The ratio
exhibits anomalous enhancement at the two critical points due to the sudden
change in the density of states. Despite a breakdown of the quasiparticle
description in one dimension, two important features of the Fermi liquid are
retained, namely the specific heat is linearly proportional to temperature
whereas the susceptibility is independent of temperature. In contrast to the
phenomenological TLL parameter, the Wilson ratio provides a powerful parameter
for testing universal quantum liquids of interacting fermions in one, two and
three dimensions.Comment: 5+2 pages, 4+1 figures, Eq. (4) is proved, figures were refine
Integrable open boundary conditions for the Bariev model of three coupled XY spin chains
The integrable open-boundary conditions for the Bariev model of three coupled
one-dimensional XY spin chains are studied in the framework of the boundary
quantum inverse scattering method. Three kinds of diagonal boundary K-matrices
leading to nine classes of possible choices of boundary fields are found and
the corresponding integrable boundary terms are presented explicitly. The
boundary Hamiltonian is solved by using the coordinate Bethe ansatz technique
and the Bethe ansatz equations are derived.Comment: 21 pages, no figure
Integrable multiparametric quantum spin chains
Using Reshetikhin's construction for multiparametric quantum algebras we
obtain the associated multiparametric quantum spin chains. We show that under
certain restrictions these models can be mapped to quantum spin chains with
twisted boundary conditions. We illustrate how this general formalism applies
to construct multiparametric versions of the supersymmetric t-J and U models.Comment: 17 pages, RevTe
Charmonium dynamics in heavy ion collisions
Applying the HSD transport approach to charmonium dynamics within the
'hadronic comover model' and the 'QGP melting scenario', we show that the
suppression pattern seen at RHIC cannot be explained by the interaction with
baryons, comoving mesons and/or by color screening mechanism. The interaction
with hadrons in the late stages of the collision (when the energy density falls
below the critical) gives a sizable contribution to the suppression. On the
other hand, it does not account for the observed additional charmonium
dissociation and its dependence on rapidity. Together with the failure of the
hadron-string models to reproduce high v2 of open charm mesons, this suggests
strong pre-hadronic interaction of c-cbar with the medium at high energy
densities.Comment: 6 pages, 2 figures, talk presented at the international conference on
"Strangeness in Quark Matter", 24-29 June 2007, Levoca, Slovaki
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