103 research outputs found
Sure success partial search
Partial search has been proposed recently for finding the target block
containing a target element with fewer queries than the full Grover search
algorithm which can locate the target precisely. Since such partial searches
will likely be used as subroutines for larger algorithms their success rate is
important. We propose a partial search algorithm which achieves success with
unit probability
Scalar products in generalized models with SU(3)-symmetry
We consider a generalized model with SU(3)-invariant R-matrix, and review the
nested Bethe Ansatz for constructing eigenvectors of the transfer matrix. A sum
formula for the scalar product between generic Bethe vectors, originally
obtained by Reshetikhin [11], is discussed. This formula depends on a certain
partition function Z(\{\lambda\},\{\mu\}|\{w\},\{v\}), which we evaluate
explicitly. In the limit when the variables \{\mu\} or \{v\} approach infinity,
this object reduces to the domain wall partition function of the six-vertex
model Z(\{\lambda\}|\{w\}). Using this fact, we obtain a new expression for the
off-shell scalar product (between a generic Bethe vector and a Bethe
eigenvector), in the case when one set of Bethe variables tends to infinity.
The expression obtained is a product of determinants, one of which is the
Slavnov determinant from SU(2) theory. It extends a result of Caetano [13].Comment: 28 pages, 12 figures, greatly lengthened exposition in v3; 2
appendices and extra references adde
Theory of spinor Fermi and Bose gases in tight atom waveguides
Divergence-free pseudopotentials for spatially even and odd-wave interactions
in spinor Fermi gases in tight atom waveguides are derived. The Fermi-Bose
mapping method is used to relate the effectively one-dimensional fermionic
many-body problem to that of a spinor Bose gas. Depending on the relative
magnitudes of the even and odd-wave interactions, the N-atom ground state may
have total spin S=0, S=N/2, and possibly also intermediate values, the case
S=N/2 applying near a p-wave Feshbach resonance, where the N-fermion ground
state is space-antisymmetric and spin-symmetric. In this case the fermionic
ground state maps to the spinless bosonic Lieb-Liniger gas. An external
magnetic field with a longitudinal gradient causes a Stern-Gerlach spatial
separation of the corresponding trapped Fermi gas with respect to various
values of .Comment: 4+ pages, 1 figure, revtex4. Submitted to PRA. Minor corrections of
typos and notatio
Determinant Representations for Correlation Functions of Spin-1/2 XXX and XXZ Heisenberg Magnets
We consider correlation functions of the spin-\half XXX and XXZ Heisenberg
chains in a magnetic field. Starting from the algebraic Bethe Ansatz we derive
representations for various correlation functions in terms of determinants of
Fredholm integral operators.Comment: 23 pages, TeX, BONN-TH-94-14, revised version: typos correcte
Universal correlations of one-dimensional interacting electrons in the gas phase
We consider dynamical correlation functions of short range interacting
electrons in one dimension at finite temperature. Below a critical value of the
chemical potential there is no Fermi surface anymore, and the system can no
longer be described as a Luttinger liquid. Its low temperature thermodynamics
is that of an ideal gas. We identify the impenetrable electron gas model as a
universal model for the gas phase and present exact and explicit expressions
for the asymptotics of correlation functions at small temperatures, in the
presence of a magnetic field.Comment: 4 pages, Revte
Higgs Structures of Dyonic Instantons
We study Higgs field configurations of dyonic instantons in spontaneously
broken (4+1)-dimensional Yang-Mills theory. The adjoint scalar field solutions
to the covariant Laplace equation in the ADHM instanton background are
constructed in general noncanonical basis, and they are used to study
explicitly the Higgs field configurations of dyonic instantons when the gauge
fields are taken by Jackiw-Nohl-Rebbi instanton solutions. For these solutions
corresponding to small instanton number we then consider in some detail the
zero locus of the Higgs field, which describes the cross section of supertubes
connecting parallel D4-branes in string theory. Also the information on the
Higgs zeroes is used to discuss the residual gauge freedom concerning the
Jackiw-Nohl-Rebbi solutions.Comment: 1+27 pages, 6 figure
The Hubbard chain: Lieb-Wu equations and norm of the eigenfunctions
We argue that the square of the norm of the Hubbard wave function is
proportional to the determinant of a matrix, which is obtained by linearization
of the Lieb-Wu equations around a solution. This means that in the vicinity of
a solution the Lieb-Wu equations are non-degenerate, if the corresponding wave
function is non-zero. We further derive an action that generates the Lieb-Wu
equations and express our determinant formula for the square of the norm in
terms of the Hessian determinant of this action.Comment: 11 pages, Late
Correlations in the impenetrable electron gas
We consider non-relativistic electrons in one dimension with infinitely
strong repulsive delta function interaction. We calculate the long-time,
large-distance asymptotics of field-field correlators in the gas phase. The gas
phase at low temperatures is characterized by the ideal gas law. We calculate
the exponential decay, the power law corrections and the constant factor of the
asymptotics. Our results are valid at any temperature. They simplify at low
temperatures, where they are easily recognized as products of free fermionic
correlation functions with corrections arising due to the interaction.Comment: 17 pages, Late
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