412 research outputs found
Time Reversal Invariance Violating and Parity Conserving effects in Neutron Deuteron Scattering
Time reversal invariance violating parity conserving effects for low energy
elastic neutron deuteron scattering are calculated for meson exchange and
EFT-type of potentials in a Distorted Wave Born Approximation, using realistic
hadronic wave functions, obtained by solving three-body Faddeev equations in
configuration space.Comment: There was a technical mistake in calculations due to singular
behavior of Yukawa functions at short range. We corrected the integration
algorithm. There were some typos which are corrected. arXiv admin note: text
overlap with arXiv:1104.305
Time Reversal Invariance Violation in Neutron Deuteron Scattering
Time reversal invariance violating (TRIV) effects for low energy elastic
neutron deuteron scattering are calculated for meson exchange and EFT-type of
TRIV potentials in a Distorted Wave Born Approximation, using realistic
hadronic strong interaction wave functions, obtained by solving three-body
Faddeev equations in configuration space. The relation between TRIV and parity
violating observables are discussed
Oscillations of the superconducting critical current in Nb-Cu-Ni-Cu-Nb junctions
We report on experimental studies of superconductor-ferromagnet layered
structures. Strong oscillations of the critical supercurrent were observed with
the thickness variation of the ferromagnet. Using known microscopic parameters
of Ni, we found reasonable agreement between the period of oscillations and the
decay of the measured critical current, and theoretical calculations.Comment: 5 page
Parity violation in low energy neutron deuteron scattering
Parity violating effects for low energy elastic neutron deuteron scattering
are calculated for DDH and EFT-type of weak potentials in a Distorted Wave Born
Approximation, using realistic hadronic strong interaction wave functions,
obtained by solving three-body Faddeev equations in configuration space. The
results of relation between physical observables and low energy constants can
be used to fix low energy constants from experiments. Potential model
dependencies of parity violating effects are discussed.Comment: version accepted for publication in Phys. Rev.
Beyond Moore's technologies: operation principles of a superconductor alternative
The predictions of Moore's law are considered by experts to be valid until
2020 giving rise to "post-Moore's" technologies afterwards. Energy efficiency
is one of the major challenges in high-performance computing that should be
answered. Superconductor digital technology is a promising post-Moore's
alternative for the development of supercomputers. In this paper, we consider
operation principles of an energy-efficient superconductor logic and memory
circuits with a short retrospective review of their evolution. We analyze their
shortcomings in respect to computer circuits design. Possible ways of further
research are outlined.Comment: OPEN ACCES
Comprehensive automated system for studying the theory of electrical circuits
The article considers the implementation of a package of application software that performs a number of specific tasks for students and teachers of disciplines related to the studying of electrical circuits in higher educational institutes. The C++ programming language tecnologies were used with Qt5 framework, window of WinForms with a graphical context OpenGL
Loss of Andreev Backscattering in Superconducting Quantum Point Contacts
We study effects of magnetic field on the energy spectrum in a
superconducting quantum point contact. The supercurrent induced by the magnetic
field leads to intermode transitions between the electron waves that pass and
do not pass through the constriction. The latter experience normal reflections
which couple the states with opposite momenta inside the quantum channel and
create a minigap in the energy spectrum that depends on the magnetic field
New Enhanced Tunneling in Nuclear Processes
The small sub-barrier tunneling probability of nuclear processes can be
dramatically enhanced by collision with incident charged particles.
Semiclassical methods of theory of complex trajectories have been applied to
nuclear tunneling, and conditions for the effects have been obtained. We
demonstrate the enhancement of alpha particle decay by incident proton with
energy of about 0.25 MeV. We show that the general features of this process are
common for other sub-barrier nuclear processes and can be applied to nuclear
fission.Comment: RevTex4, 2 figure
Parity violation in radiative neutron capture on deuteron
Parity violating (PV) effects in neutron-deuteron radiative capture are
studied using Desplanques, Donoghue, and Holstein (DDH) and effective field
theory weak potentials. The values of PV effects are calculated using wave
functions, obtained by solving three-body Faddeev equations in configuration
space for phenomenological strong potentials. The relations between physical
observables and low-energy constants are presented, and dependencies of the
calculated PV effects on strong and weak potentials are discussed. The
presented analysis shows the possible reason for the existing discrepancy in PV
nuclear data analysis using the DDH approach and reveals a new opportunity to
study short range interactions in nuclei
Numerical adiabatic potentials of orthorhombic Jahn-Teller effects retrieved from ultrasound attenuation experiments. Application to the SrF2:Cr crystal
A methodology is worked out to retrieve the numerical values of all the main
parameters of the six-dimensional adiabatic potential energy surface (APES) of
a polyatomic system with a quadratic T-term Jahn-Teller effect (JTE) from
ultrasound experiments. The method is based on a verified assumption that
ultrasound attenuation and speed encounter anomalies when the direction of
propa- gation and polarization of its wave of strain coincides with the
characteristic directions of symmetry breaking in the JTE. For the SrF2:Cr
crystal, employed as a basic example, we observed anomaly peaks in the
temperature dependence of attenuation of ultrasound at frequencies of 50-160
MHz in the temperature interval of 40-60 K for the wave propagating along the
[110] direction, for both the longitudinal and shear modes, the latter with two
polarizations along the [001] and [110] axes, respectively. We show that these
anomalies are due to the ultrasound relaxation by the system of non-interacting
Cr2+ JT centers with orthorhombic local distortions. The interpretation of the
ex- perimental findings is based on the T2g (eg +t2g) JTE problem including the
linear and quadratic terms of vibronic interactions in the Hamiltonian and the
same-symmetry modes reduced to one interaction mode. Combining the experimental
results with a theoretical analysis we show that on the complicated
six-dimensional APES of this system with three tetragonal, four trigonal, and
six orthorhombic extrema points, the latter are global minima, while the former
are saddle points, and we estimate numerically all the main parameters of this
surface, including the linear and quadratic vibronic coupling constants, the
primary force constants, the coordinates of all the extrema points and their
energies, the energy barrier between the orthorhombic minima, and the tunneling
splitting of the ground vibrational states.Comment: 8 pages, 3 figure
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