347 research outputs found
Directional flow of solitons with asymmetric potential wells: Soliton diode
We study the flow of bright solitons through two asymmetric potential wells.
The scattering of a soliton by certain type of single potential wells, e.g.,
Gaussian or Rosen-Morse, is distinguished by a critical velocity above which
solitons can transmit almost completely and below which solitons can reflect
nearly perfectly. For two such wells in series with certain parameter
combinations, we find that there is an appreciable velocity range for which
solitons can propagate in one direction only. Our study shows that this
directional propagation or diode behavior is due to a combined effect of the
sharp transition in the transport coefficients at the critical velocity and a
slight reduction in the center-of-mass speed of the soliton while it travels
across a potential well.Comment: 7 pages, 5 figure
Unidirectional flow of flat-top solitons
We numerically demonstrate the unidirectional flow of flat-top solitons when
interacting with two reflectionless potential wells with slightly different
depths. The system is described by a nonlinear Schr\"{o}dinger equation with
dual nonlinearity. The results show that for shallow potential wells, the
velocity window for unidirectional flow is larger than for deeper potential
wells. A wider flat-top solitons also have a narrow velocity window for
unidirectional flow than those for thinner flat-top solitons.Comment: 5 pages, 7 figure
Unidirectional soliton flows in PT-symmetric potentials
We study the soliton scattering by parity-time- (PT) symmetric potentials and demonstrate that, for a certain range of parameters, both single and multiple soliton scattering exhibit almost perfect unidirectional flow. We employ direct numerical simulati
Dimensional and Temperature Crossover in Trapped Bose Gases
We investigate the long-range phase coherence of homogeneous and trapped Bose
gases as a function of the geometry of the trap, the temperature, and the
mean-field interactions in the weakly interacting limit. We explicitly take
into account the (quasi)condensate depletion due to quantum and thermal
fluctuations, i.e., we include the effects of both phase and density
fluctuations. In particular, we determine the phase diagram of the gas by
calculating the off-diagonal one-particle density matrix and discuss the
various crossovers that occur in this phase diagram and the feasibility of
their experimental observation in trapped Bose gases.Comment: One figure added, typos corrected, refernces adde
Two-component Bose gas in an optical lattice at single-particle filling
The Bose-Hubbard model of a two-fold degenerate Bose gas is studied in an
optical lattice with one particle per site and virtual tunneling to empty and
doubly-occupied sites. An effective Hamiltonian for this system is derived
within a continued-fraction approach. The ground state of the effective model
is studied in mean-field approximation for a modulated optical lattice. A
dimerized mean-field state gives a Mott insulator whereas the lattice without
modulations develops long-range correlated phase fluctuations due to a
Goldstone mode. This result is discussed in comparison with the superfluid and
the Mott-insulating state of a single-component hard-core Bose.Comment: 11 page
Mermin-Ho vortex in ferromagnetic spinor Bose-Einstein condensates
The Mermin-Ho and Anderson-Toulouse coreless non-singular vortices are
demonstrated to be thermodynamically stable in ferromagnetic spinor
Bose-Einstein condensates with the hyperfine state F=1. The phase diagram is
established in a plane of the rotation drive vs the total magnetization by
comparing the energies for other competing non-axis-symmetric or singular
vortices. Their stability is also checked by evaluating collective modes.Comment: 4 pages, 4 figure
Customer Satisfaction with Islamic Banks: A Case Study of Al Rajhi Bank
Abstract. This study aims to identify the factors that lead to the level of customer satisfaction about online services provided by Al Rajhi Bank, which is the largest Islamic Bank in the world. This study is conducted on a sample of customers who deal with Al Rajhi Bank in Qassim region, Saudi Arabia by measuring different constructs such as; reliability, efficiency, response, and empathy which have been taken as determinants of customer satisfaction. The sample size of the respondents is 184 clients. The study reveals that reliability, efficiency, response and empathy all have a positive and significant impact on customer satisfaction. In addition, the results also show that the dimension “efficiency” plays a leading role in the customer satisfaction. This means that indicators of efficiency like ease of service, diversity of online services, organized information and transactions in reasonable times frame are the most important factors in achieving customer satisfaction.</p
- …