5,671 research outputs found
Spin-Peierls-like phases in magnetoelastic antiferromagnetic chain at 1/3 magnetization
We investigate elastic deformations of spin antiferromagnetic
Heisenberg chains, at magnetization, coupled to phonons in
the adiabatic approximation. Using a bosonization approach we predict the
existence of non-homogeneous trimerized magnetoelastic phases. A rich ground
state phase diagram is found, including classical and quantum plateau states
for the magnetic sector as well as inequivalent lattice deformations within
each magnetic phase. The analytical results are supported by exact
diagonalization of small clusters.Comment: 7 pages, 5 figure
From perfect to fractal transmission in spin chains
Perfect state transfer is possible in modulated spin chains, imperfections
however are likely to corrupt the state transfer. We study the robustness of
this quantum communication protocol in the presence of disorder both in the
exchange couplings between the spins and in the local magnetic field. The
degradation of the fidelity can be suitably expressed, as a function of the
level of imperfection and the length of the chain, in a scaling form. In
addition the time signal of fidelity becomes fractal. We further characterize
the state transfer by analyzing the spectral properties of the Hamiltonian of
the spin chain.Comment: 8 pages, 10 figures, published versio
Engineering fidelity echoes in Bose-Hubbard Hamiltonians
We analyze the fidelity decay for a system of interacting bosons described by
a Bose-Hubbard Hamiltonian. We find echoes associated with "non-universal"
structures that dominate the energy landscape of the perturbation operator.
Despite their classical origin, these echoes persist deep into the quantum
(perturbative) regime and can be described by an improved random matrix
modeling. In the opposite limit of strong perturbations (and high enough
energies), classical considerations reveal the importance of self-trapping
phenomena in the echo efficiency.Comment: 6 pages, use epl2.cls class, 5 figures Cross reference with nlin,
quant-phy
Quantum Breathing of an Impurity in a One-dimensional Bath of Interacting Bosons
By means of time-dependent density-matrix renormalization-group (TDMRG) we
are able to follow the real-time dynamics of a single impurity embedded in a
one-dimensional bath of interacting bosons. We focus on the impurity breathing
mode, which is found to be well-described by a single oscillation frequency and
a damping rate. If the impurity is very weakly coupled to the bath, a
Luttinger-liquid description is valid and the impurity suffers an
Abraham-Lorentz radiation-reaction friction. For a large portion of the
explored parameter space, the TDMRG results fall well beyond the
Luttinger-liquid paradigm.Comment: 10 pages, 7 figures, main text and supplementary material merged in a
single PRB style documen
Effects of varying solar-view geometry and canopy structure on solar-induced chlorophyll fluorescence and PRI
Exact solution for a diffusive nonequilibrium steady state of an open quantum chain
We calculate a nonequilibrium steady state of a quantum XX chain in the
presence of dephasing and driving due to baths at chain ends. The obtained
state is exact in the limit of weak driving while the expressions for one- and
two-point correlations are exact for an arbitrary driving strength. In the
steady state the magnetization profile and the spin current display diffusive
behavior. Spin-spin correlation function on the other hand has long-range
correlations which though decay to zero in either the thermodynamical limit or
for equilibrium driving. At zero dephasing a nonequilibrium phase transition
occurs from a ballistic transport having short-range correlations to a
diffusive transport with long-range correlations.Comment: 5 page
Comparison between disordered quantum spin 1/2 chains
We study the magnetic properties of two types of one dimensional XX spin 1/2
chains. The first type has only nearest neighbor interactions which can be
either antiferromagnetic or ferromagnetic and the second type which has both
nearest neighbor and next nearest neighbor interactions, but only
antiferromagnetic in character. We study these systems in the presence of low
transverse magnetic fields both analytically and numerically. Comparison of
results show a close relation between the two systems, which is in agreement
with results previously found in Heisenberg chains by means of a numerical real
space renormalization group procedure.Comment: 7 page
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