37 research outputs found
Simulating Scattering of Composite Particles
We develop a non-perturbative approach to simulating scattering on classical
and quantum computers, in which the initial and final states contain a fixed
number of composite particles. The construction is designed to mimic a particle
collision, wherein two composite particles are brought in contact. The initial
states are assembled via consecutive application of operators creating
eigenstates of the interacting theory from vacuum. These operators are defined
with the aid of the M{\o}ller wave operator, which can be constructed using
such methods as adiabatic state preparation or double commutator flow equation.
The approach is well-suited for studying strongly coupled systems in both
relativistic and non-relativistic settings. For relativistic systems, we employ
the language of light-front quantization, which has been previously used for
studying the properties of individual bound states, as well as for simulating
their scattering in external fields, and is now adopted to the studies of
scattering of bound state systems.
For simulations on classical computers, we describe an algorithm for
calculating exact (in the sense of a given discretized theory) scattering
probabilities, which has cost (memory and time) exponential in momentum grid
size. Such calculations may be interesting in their own right and can be used
for benchmarking results of a quantum simulation algorithm, which is the main
application of the developed framework. We illustrate our ideas with an
application to the theory in .Comment: 32 pages, 10 figures, 3 table
The nonlinear effects in 2DEG conductivity investigation by an acoustic method
The parameters of two-dimensional electron gas (2DEG) in a GaAs/AlGaAs
heterostructure were determined by an acoustical (contactless) method in the
delocalized electrons region (2.5T). Nonlinear effects in Surface
Acoustic Wave (SAW) absorption by 2DEG are determined by the electron heating
in the electric field of SAW, which may be described in terms of electron
temperature . The energy relaxation time is determined
by the scattering at piezoelectric potential of acoustic phonons with strong
screening. At different SAW frequencies the heating depends on the relationship
between and 1 and is determined either by the
instantaneously changing wave field (), or by the
average wave power ().Comment: RevTeX, 5 pages, 3 PS-figures, submitted to Physica Status
Sol.(Technical corrections in PS-figs
Giant Spin Relaxation Anisotropy in Zinc-Blende Heterostructures
Spin relaxation in-plane anisotropy is predicted for heterostructures based
on zinc-blende semiconductors. It is shown that it manifests itself especially
brightly if the two spin relaxation mechanisms (D'yakonov-Perel' and Rashba)
are comparable in efficiency. It is demonstrated that for the quantum well
grown along the [0 0 1] direction, the main axes of spin relaxation rate tensor
are [1 1 0] and [1 -1 0].Comment: 3 pages, NO figure