3,689 research outputs found
A Dynamical System with Q-deformed Phase Space Represented in Ordinary Variable Spaces
Dynamical systems associated with a q-deformed two dimensional phase space
are studied as effective dynamical systems described by ordinary variables. In
quantum theory, the momentum operator in such a deformed phase space becomes a
difference operator instead of the differential operator. Then, using the path
integral representation for such a dynamical system, we derive an effective
short-time action, which contains interaction terms even for a free particle
with q-deformed phase space. Analysis is also made on the eigenvalue problem
for a particle with q-deformed phase space confined in a compact space. Under
some boundary conditions of the compact space, there arises fairly different
structures from case in the energy spectrum of the particle and in the
corresponding eigenspace .Comment: 17page, 2 figure
Quantum gate using qubit states separated by terahertz
A two-qubit quantum gate is realized using electronic excited states in a
single ion with an energy separation on the order of a terahertz times the
Planck constant as a qubit. Two phase locked lasers are used to excite a
stimulated Raman transition between two metastable states and
separated by 1.82 THz in a single trapped Ca ion to
construct a qubit, which is used as the target bit for the Cirac-Zoller
two-qubit controlled NOT gate. Quantum dynamics conditioned on a motional qubit
is clearly observed as a fringe reversal in Ramsey interferometry.Comment: 4 pages, 4 figure
Phase Transitions in the NMSSM
We study phase transitions in the Next-to-Minimal Supersymmetric Standard
Model (NMSSM) with the weak scale vacuum expectation values of the singlet
scalar, constrained by Higgs spectrum and vacuum stability. We find four
different types of phase transitions, three of which have two-stage nature. In
particular, one of the two-stage transitions admits strongly first order
electroweak phase transition, even with heavy squarks. We introduce a
tree-level explicit CP violation in the Higgs sector, which does not affect the
neutron electric dipole moment. In contrast to the MSSM with the CP violation
in the squark sector, a strongly first order phase transition is not so
weakened by this CP violation.Comment: 21 pages, 8 figure
CP Violation in the Higgs Sector and Phase Transition in the MSSM
We investigate the electroweak phase transition in the presence of a large CP
violation in the squark sector of the MSSM. When the CP violation is large,
scalar-pseudoscalar mixing of the Higgs bosons occurs and a large CP violation
in the Higgs sector is induced. It, however, weakens first-order phase
transition before the mixing reaches the maximal. Even when the CP violation in
the squark sector is not so large that the phase transition is strongly first
order, the phase difference between the broken and symmetric phase regions
grows to O(1), which leads to successful baryogenesis, when the charged Higgs
bosons is light.Comment: 18 pages, 6 figures, LaTeX2
Scattering with Baryon Number Violation -- The Case of Higgs Particle Production --
\noindent A formalism based on path-integral expression of time-evolution
operator during tunneling at a finite energy proposed by the authors is applied
to gauge-Higgs system to produce Higgs particles with .
Instead of starting from instanton tunneling at the zero energy, a classical
bounce solution giving sphaleron (instanton) action at high (low) energies is
used as the tunneling configuration. Fourier transform of the bounce
configuration in coherent state expression at the entrance and exit of the
tunneling plays an important role. Numerical results at various energies for
are given. Though the cross section with
results from a severe cancellation of several large quantities in the leading
order as occured in the instanton calculus, it seems unlikely that the cross
section grows as largely as to reach unitarity bound at energies . It is pointed out that the actual value of the
gauge coupling constant may be too large to take the weak coupling limit.}Comment: modified PHYZZX(included), 4 Figures (not included), SAGA-HE-46 :
KYUSHU-HET-
Hyperintense vessel sign on fluid-attenuated inversion recovery MR imaging is reduced by gadolinium
The HVS on FLAIR imaging is a useful marker of acute ischemic stroke. We investigated whether prior administration of gadolinium-based contrast hindered detection of this sign on images from subjects with acute nonlacunar ischemic stroke <4.5 hours after onset. Both blinded and comparative unblinded analyses showed significantly reduced HVS detection on postcontrast images. We suggest that assessment for this sign should be performed on images acquired prior to contrast administration
Charge Generation in the Oscillating Background
The preheating after the inflation, which can be interpreted as particle
creation in the oscillating inflaton background, provides a state far from
thermal equilibrium. We extend the field theoretical treatment of the
preheating by Linde et al. to the case of multicomponent complex scalars to
show that some charges are created in this process, if C and CP are violated. A
new possibility of baryogenesis based on this mechanism is also discussed.Comment: 18 pages, LaTeX 2e, 3 eps figure
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