22 research outputs found
Reply to "Comment on 'Kinetic theory for a mobile impurity in a degenerate Tonks-Girardeau gas'"
In our recent paper [Phys. Rev. E 90, 032132 (2014)] we have studied the
dynamics of a mobile impurity particle weakly interacting with the
Tonks-Girardeau gas and pulled by a small external force, . Working in the
regime when the thermodynamic limit is taken prior to the small force limit, we
have found that the Bloch oscillations of the impurity velocity are absent in
the case of a light impurity. Further, we have argued that for a light impurity
the steady state drift velocity, , remains finite in the limit
. These results are in contradiction with earlier works by
Gangardt, Kamenev and Schecter [Phys. Rev. Lett. 102, 070402 (2009), Annals of
Physics 327, 639 (2012)]. One of us (OL) has conjectured [Phys. Rev. A 91,
040101 (2015)] that the central assumption of these works - the adiabaticity of
the dynamics - can break down in the thermodynamic limit. In the preceding
Comment [Phys. Rev. E 92, 016101 (2015)] Schecter, Gangardt and Kamenev have
argued against this conjecture and in support of the existence of Bloch
oscillations and linearity of . They have suggested that the ground
state of the impurity-fluid system is a quasi-bound state and that this is
sufficient to ensure adiabaticity in the thermodynamic limit. Their analytical
argument is based on a certain truncation of the Hilbert space of the system.
We argue that extending the results and intuition based on their truncated
model on the original many-body problem lacks justification
Momentum relaxation of a mobile impurity in a one-dimensional quantum gas
We investigate the time evolution of the momentum of an impurity atom
injected into a degenerate Tonks-Girardeau gas. We establish that given an
initial momentum the impurity relaxes to a steady state with a
non-vanishing momentum The nature of the steady state is found to
depend drastically on whether the masses of the impurity and the host are equal
or not. This is due to multiple coherent scattering processes leading to a
resonant interaction between the impurity and the host in the case of equal
masses. The dependence of on remains non-trivial even in the
limit of vanishing interaction between the impurity and host particles. In this
limit is found explicitly
Neutrino oscillations: deriving the plane-wave approximation in the wave-packet approach
The plane-wave approximation is widely used in the practical calculations
concerning neutrino oscillations. A simple derivation of this approximation
starting from the neutrino wave-packet framework is presented.Comment: Presented at the 36th ITEP Winter School of Physics, session
"Particle Physics", February 8-16, 2008, Otradnoe, Russi
Neutrino wave function and oscillation suppression
We consider a thought experiment, in which a neutrino is produced by an
electron on a nucleus in a crystal. The wave function of the oscillating
neutrino is calculated assuming that the electron is described by a wave
packet. If the electron is relativistic and the spatial size of its wave packet
is much larger than the size of the crystal cell, then the wave packet of the
produced neutrino has essentially the same size as the wave packet of the
electron. We investigate the suppression of neutrino oscillations at large
distances caused by two mechanisms: 1) spatial separation of wave packets
corresponding to different neutrino masses; 2) neutrino energy dispersion for
given neutrino mass eigenstates. We resolve contributions of these two
mechanisms.Comment: 7 page
mu->e Gamma decay versus mu->eee bound and lepton flavor violating processes in supernova
Even tiny lepton flavor violation (LFV) due to some New Physics is able to
alter the conditions inside a collapsing supernova core and probably to
facilitate the explosion. LFV emerges naturally in a See-Saw type II model of
neutrino mass generation. Experimentally LFV is constrained by rare lepton
decay searches. In particular, strong bounds are imposed on the mu->eee
branching ratio and on the mu-e conversion probability in muonic gold.
Currently the mu->e gamma decay is under investigation in the MEG experiment
which aims at dramatic increase of sensitivity in the next three years. We
search for a See-Saw type II LFV pattern which fits all the experimental
constraints, provides Br(mu->e gamma) not less than Br(mu->eee) and ensures a
rate of LFV processes in supernova high enough to modify the supernova physics.
These requirements are sufficient to eliminate almost all freedom in the model.
In particular, they lead to a prediction 0.5*10^(-12) e gamma)<
6*10^(-12), which is testable by MEG in the nearest future. The considered
scenario also constrains neutrino mass-mixing pattern and provides lower and
upper bounds on tau-lepton LFV decays. We also briefly discuss a model with a
single bilepton in which the mu->eee decay is absent at the tree level.Comment: v2 is substantially extended compared to v1; new results are
presente
Neutrino oscillations in Kerr-Newman space-time
The mass neutrino oscillation in Kerr-Newman(K-N) space-time is studied in
the plane , and the general equations of oscillation phases
are given. The effect of the rotation and electric charge on the phase is
presented. Then, we consider three special cases: (1) The neutrinos travel
along the geodesics with the angular momentum in the equatorial plane.
(2) The neutrinos travel along the geodesics with L=0 in the equatorial plane.
(3) The neutrinos travel along the radial geodesics at the direction
. At last, we calculate the proper oscillation length in the K-N
space time. The effect of the gravitational field on the oscillation length is
embodied in the gravitational red shift factor. When the neutrino travels out
of the gravitational field, the blue shift of the oscillation length takes
place. We discussed the variation of the oscillation length influenced by the
gravitational field strength, the rotation and charge .Comment: 20 pages, no figure