3,908 research outputs found
Flat-band excitonic states in Kagome lattice on semiconductor surface
Excitonic properties in the Kagome lattice system, which is produced by
quantum wires on semiconductor surfaces, are investigated by using the exact
diagonalization of a tight binding model. It is shown that due to the existence
of flat bands the binding energy of exciton becomes remarkably large in the
two-dimensional Kagome lattice compared to that in one-dimensional lattice, and
the exciton Bohr radius is quite small as large as a lattice constant. We also
discuss the magnetic field effects on the exciton binding energy and the
stability of exciton against the creation of charged exciton and biexciton.Comment: 5 pages, 5 figure
Classical and Quantum Cosmology of Multigravity
Recently, a multigraviton theory on a simple closed circuit graph
corresponding to the discretization of compactification of the
Kaluza-Klein (KK) theory has been considered. In the present paper, we extend
this theory to that on a general graph and study what modes of particles are
included. Furthermore, we generalize it in a possible nonlinear theory based on
the vierbein formalism and study classical and quantum cosmological solutions
in the theory. We found that scale factors in a solution for this theory repeat
acceleration and deceleration.Comment: 17 pages, 15 figures, RevTeX4.1, revised versio
Mutual Information and Boson Radius in c=1 Critical Systems in One Dimension
We study the generic scaling properties of the mutual information between two
disjoint intervals, in a class of one-dimensional quantum critical systems
described by the c=1 bosonic field theory. A numerical analysis of a spin-chain
model reveals that the mutual information is scale-invariant and depends
directly on the boson radius. We interpret the results in terms of correlation
functions of branch-point twist fields. The present study provides a new way to
determine the boson radius, and furthermore demonstrates the power of the
mutual information to extract more refined information of conformal field
theory than the central charge.Comment: 4.1 pages, 5 figure
The Integrals of Motion for the Deformed W-Algebra II: Proof of the commutation relations
We explicitly construct two classes of infinitly many commutative operators
in terms of the deformed W-algebra , and give proofs of the
commutation relations of these operators. We call one of them local integrals
of motion and the other nonlocal one, since they can be regarded as elliptic
deformation of local and nonlocal integrals of motion for the algebra.Comment: Dedicated to Professor Tetsuji Miwa on the occasion on the 60th
birthda
Gravitational Effects of Quantum Fields in the Interior of a Cylindrical Black Hole
The gravitational back-reaction is calculated for the conformally invariant
scalar field within a black cosmic string interior with cosmological constant.
Using the perturbed metric, the gravitational effects of the quantum field are
calculated. It is found that the perturbations initially strengthen the
singularity. This effect is similar to the case of spherical symmetry (without
cosmological constant). This indicates that the behaviour of quantum effects
may be universal and not dependent on the geometry of the spacetime nor the
presence of a non-zero cosmological constant.Comment: 13 pages, 1 figure, uses AMS package. D.E. solution corrected. Some
qualitative results are change
Precise determination of two-carrier transport properties in the topological insulator TlBiSe
We report the electric transport study of the three-dimensional topological
insulator TlBiSe. We applied a newly developed analysis procedure and
precisely determined two-carrier transport properties. Magnetotransport
properties revealed a multicarrier conduction of high- and low-mobility
electrons in the bulk, which was in qualitative agreement with angle-resolved
photoemission results~[K. Kuroda , Phys. Rev. Lett. , 146801
(2010)]. The temperature dependence of the Hall mobility was explained well
with the conventional Bloch-Gr{\"u}neisen formula and yielded the Debye
temperature ~K. The results indicate that the
scattering of bulk electrons is dominated by acoustic phonons.Comment: 6 pages, 5 figures, to be published in Physical Review
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