1,394 research outputs found
Exotic phase separation in one-dimensional hard-core boson system with two- and three-body interactions
We investigate the ground state phase diagram of hard-core boson system with
repulsive two-body and attractive three-body interactions in one-dimensional
optic lattice. When these two interactions are comparable and increasing the
hopping rate, physically intuitive analysis indicates that there exists an
exotic phase separation regime between the solid phase with charge density wave
order and superfluid phase. We identify these phases and phase transitions by
numerically analyzing the density distribution, structure factor of
density-density correlation function, three-body correlation function and von
Neumann entropy estimator obtained by density matrix renormalization group
method. These exotic phases and phase transitions are expected to be observed
in the ultra-cold polar molecule experiments by properly tuning interaction
parameters, which is constructive to understand the physics of ubiquitous
insulating-superconducting phase transitions in condensed matter systems
Maximal violation of Clauser-Horne-Shimony-Holt inequality for four-level systems
Clauser-Horne-Shimony-Holt inequality for bipartite systems of 4-dimension is
studied in detail by employing the unbiased eight-port beam splitters
measurements. The uniform formulae for the maximum and minimum values of this
inequality for such measurements are obtained. Based on these formulae, we show
that an optimal non-maximally entangled state is about 6% more resistant to
noise than the maximally entangled one. We also give the optimal state and the
optimal angles which are important for experimental realization.Comment: 7 pages, three table
Global phase diagram of three-dimensional extended Boson Hubbard model - a continuous time Quantum Monte Carlo study
We present the global phase diagram of the extended boson Hubbard model on a
simple cubic lattice by quantum Monte Carlo simulation with worm update
algorithm. Four kinds of phases are supported by this model, including
superfluid, supersolid, Mott, and charge density wave (CDW) states, which are
identified in the phase diagram of chemical potential versus nearest
neighbor interaction V . By changing the chemical potential, a continuous
transition is found from the Mott phase to a superfluid phase without breaking
the translational symmetry. For an insulating CDW state, adding particles to it
gives rise to a continuous transition to a supersolid phase, while removing
particles usually leads to a first-order one to either supersolid or superfluid
phase. By tuning the nearest neighbor interaction, one can realize the
transition between two insulating phases, Mott and CDW with the same particle
density, which turns out to be of the first-order. We also demonstrate that a
supersolid phase with average particle density less than 1/2 can exist in a
small region of - V phase diagram
Lattice distortion induced first and second order topological phase transition in rectangular high-T superconducting monolayer
We theoretically study the lattice distortion induced first and second order
topological phase transition in rectangular FeSeTe monolayer.
When compressing the lattice constant in one direction, our first principles
calculation shows that the FeSeTe undergoes a band inversion at
point in a wide dopping range, say , which ensures
coexistence of the topological band state and the high-T
superconductivity. This unidirectional pressure also leads to the C
symmetry breaking which is necessary for the monolayer FeSeTe to
support Majorana corner states in the either presence or absence of
time-reversal symmetry. Particularly, we use methods to fit the band
structure from the first principles calculation and found that the edge states
along the and directions have different Dirac energy due to
C symmetry breaking. This is essential to obtain Majorana corner states in
D class without concerning the details of the superconducting pairing
symmetries and Zeeman form, which can potentially bring advantages in the
experimental implementation.Comment: 6 pages, 4 figure
The film thickness dependent thermal stability of Al2O3:Ag thin films as high-temperature solar selective absorbers
The monolayer Al2O3:Ag thin films were prepared by magnetron sputtering. The microstructure and optical properties of thin film after annealing at 700 degrees C in air were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and spectrophotometer. It revealed that the particle shape, size, and distribution across the film were greatly changed before and after annealing. The surface plasmon resonance absorption and thermal stability of the film were found to be strongly dependent on the film thickness, which was believed to be associated with the evolution process of particle diffusion, agglomeration, and evaporation during annealing at high temperature. When the film thickness was smaller than 90 nm, the film SPR absorption can be attenuated until extinct with increasing annealing time due to the evaporation of Ag particles. While the film thickness was larger than 120 nm, the absorption can keep constant even after annealing for 64 h due to the agglomeration of Ag particles. On the base of film thickness results, the multilayer Al2O3:Ag solar selective thin films were prepared and the thermal stability test illustrated that the solar selectivity of multilayer films with absorbing layer thickness larger than 120 nm did not degrade after annealing at 500 degrees C for 70 h in air. It can be concluded that film thickness is an important factor to control the thermal stability of Al2O3:Ag thin films as high-temperature solar selective absorbers.</p
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