253 research outputs found
Correlations in an expanding gas of hard-core bosons
We consider a longitudinal expansion of a one-dimensional gas of hard-core
bosons suddenly released from a trap. We show that the broken translational
invariance in the initial state of the system is encoded in correlations
between the bosonic occupation numbers in the momentum space. The correlations
are protected by the integrability and exhibit no relaxation during the
expansion
Singlet-triplet transition in a lateral quantum dot
We study transport through a lateral quantum dot in the vicinity of the
singlet-triplet transition in its ground state. This transition, being sharp in
an isolated dot, is broadened to a crossover by the exchange interaction of the
dot electrons with the conduction electrons in the leads. For a generic set of
system's parameters, the linear conductance has a maximum in the crossover
region. At zero temperature and magnetic field, the maximum is the strongest.
It becomes less pronounced at finite Zeeman splitting, which leads to an
increase of the background conductance and a decrease of the conductance in the
maximum
Phase randomness in a one-dimensional disordered absorbing medium
Analytical study of the distribution of phase of the transmission coefficient
through 1D disordered absorbing system is presented. The phase is shown to obey
approximately Gaussian distribution. An explicit expression for the variance is
obtained, which shows that absorption suppresses the fluctuations of the phase.
The applicability of the random phase approximation is discussed.Comment: submitted to Phys.Rev.
- …