1,499 research outputs found
Tuning the exciton g-factor in single InAs/InP quantum dots
Photoluminescence data from single, self-assembled InAs/InP quantum dots in
magnetic fields up to 7 T are presented. Exciton g-factors are obtained for
dots of varying height, corresponding to ground state emission energies ranging
from 780 meV to 1100 meV. A monotonic increase of the g-factor from -2 to +1.2
is observed as the dot height decreases. The trend is well reproduced by sp3
tight binding calculations, which show that the hole g-factor is sensitive to
confinement effects through orbital angular momentum mixing between the
light-hole and heavy-hole valence bands. We demonstrate tunability of the
exciton g-factor by manipulating the quantum dot dimensions using pyramidal InP
nanotemplates
Rodrigues Formula for the Nonsymmetric Multivariable Laguerre Polynomial
Extending a method developed by Takamura and Takano, we present the Rodrigues
formula for the nonsymmetric multivariable Laguerre polynomials which form the
orthogonal basis for the -type Calogero model with distinguishable
particles. Our construction makes it possible for the first time to
algebraically generate all the nonsymmetric multivariable Laguerre polynomials
with different parities for each variable.Comment: 6 pages, LaTe
Coulomb and Spin blockade of two few-electrons quantum dots in series in the co-tunneling regime
We present Coulomb Blockade measurements of two few-electron quantum dots in
series which are configured such that the electrochemical potential of one of
the two dots is aligned with spin-selective leads. The charge transfer through
the system requires co-tunneling through the second dot which is in
resonance with the leads. The observed amplitude modulation of the resulting
current is found to reflect spin blockade events occurring through either of
the two dots. We also confirm that charge redistribution events occurring in
the off-resonance dot are detected indirectly via changes in the
electrochemical potential of the aligned dot.Comment: 6 pages, 5 figures, submitted to Phys. Rev.
Shape Invariance in the Calogero and Calogero-Sutherland Models
We show that the Calogero and Calogero-Sutherland models possess an N-body
generalization of shape invariance. We obtain the operator representation that
gives rise to this result, and discuss the implications of this result,
including the possibility of solving these models using algebraic methods based
on this shape invariance. Our representation gives us a natural way to
construct supersymmetric generalizations of these models, which are interesting
both in their own right and for the insights they offer in connection with the
exact solubility of these models.Comment: Latex file, 23 pages, no picture
Collective Field Description of Spin Calogero-Sutherland Models
Using the collective field technique, we give the description of the spin
Calogero-Sutherland Model (CSM) in terms of free bosons. This approach can be
applicable for arbitrary coupling constant and provides the bosonized
Hamiltonian of the spin CSM. The boson Fock space can be identified with the
Hilbert space of the spin CSM in the large limit. We show that the
eigenstates corresponding to the Young diagram with a single row or column are
represented by the vertex operators. We also derive a dual description of the
Hamiltonian and comment on the construction of the general eigenstates.Comment: 14 pages, one figure, LaTeX, with minor correction
Common Algebraic Structure for the Calogero-Sutherland Models
We investigate common algebraic structure for the rational and trigonometric
Calogero-Sutherland models by using the exchange-operator formalism. We show
that the set of the Jack polynomials whose arguments are Dunkl-type operators
provides an orthogonal basis for the rational case.Comment: 7 pages, LaTeX, no figures, some text and references added, minor
misprints correcte
Rodrigues Formula for the Nonsymmetric Multivariable Hermite Polynomial
Applying a method developed by Takamura and Takano for the nonsymmetric Jack
polynomial, we present the Rodrigues formula for the nonsymmetric multivariable
Hermite polynomial.Comment: 5 pages, LaTe
Rodrigues Formula for Hi-Jack Symmetric Polynomials Associated with the Quantum Calogero Model
The Hi-Jack symmetric polynomials, which are associated with the simultaneous
eigenstates for the first and second conserved operators of the quantum
Calogero model, are studied. Using the algebraic properties of the Dunkl
operators for the model, we derive the Rodrigues formula for the Hi-Jack
symmetric polynomials. Some properties of the Hi-Jack polynomials and the
relationships with the Jack symmetric polynomials and with the basis given by
the QISM approach are presented. The Hi-Jack symmetric polynomials are strong
candidates for the orthogonal basis of the quantum Calogero model.Comment: 17 pages, LaTeX file using jpsj.sty (ver. 0.8), cite.sty,
subeqna.sty, subeqn.sty, jpsjbs1.sty and jpsjbs2.sty (all included.) You can
get all the macros from ftp.u-tokyo.ac.jp/pub/SOCIETY/JPSJ
Families of superintegrable Hamiltonians constructed from exceptional polynomials
We introduce a family of exactly-solvable two-dimensional Hamiltonians whose
wave functions are given in terms of Laguerre and exceptional Jacobi
polynomials. The Hamiltonians contain purely quantum terms which vanish in the
classical limit leaving only a previously known family of superintegrable
systems. Additional, higher-order integrals of motion are constructed from
ladder operators for the considered orthogonal polynomials proving the quantum
system to be superintegrable
Theory of electronic transport through a triple quantum dot in the presence of magnetic field
Theory of electronic transport through a triangular triple quantum dot
subject to a perpendicular magnetic field is developed using a tight binding
model. We show that magnetic field allows to engineer degeneracies in the
triple quantum dot energy spectrum. The degeneracies lead to zero electronic
transmission and sharp dips in the current whenever a pair of degenerate states
lies between the chemical potential of the two leads. These dips can occur with
a periodicity of one flux quantum if only two levels contribute to the current
or with half flux quantum if the three levels of the triple dot contribute. The
effect of strong bias voltage and different lead-to-dot connections on
Aharonov-Bohm oscillations in the conductance is also discussed
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