362 research outputs found
Excitation of atoms in an optical lattice driven by polychromatic amplitude modulation
We investigate the mutiphoton process between different Bloch states in an
amplitude modulated optical lattice. In the experiment, we perform the
modulation with more than one frequency components, which includes a high
degree of freedom and provides a flexible way to coherently control quantum
states. Based on the study of single frequency modulation, we investigate the
collaborative effect of different frequency components in two aspects. Through
double frequency modulations, the spectrums of excitation rates for different
lattice depths are measured. Moreover, interference between two separated
excitation paths is shown, emphasizing the influence of modulation phases when
two modulation frequencies are commensurate. Finally, we demonstrate the
application of the double frequency modulation to design a
large-momentum-transfer beam splitter. The beam splitter is easy in practice
and would not introduce phase shift between two arms.Comment: 11pages, 7 figure
The Impacts of Margin-trading and Short-selling on Liquidity: Evidence from the Chinese Stock Market
Role of crystal-field-splitting and longe-range-hoppings on superconducting pairing symmetry of LaNiO
We study the bilayer two-orbital model for superconducting pairing symmetry
of LaNiO under pressure. By combining density-functional-theory
(DFT), maximally-localized-Wannier-function, and linearized Eliashberg equation
with random-phase-approximation, we find that the superconducting pairing
symmetry of LaNiO is robustly if its DFT band structure is
accurately reproduced in the downfolded model. We further show that fine-tuning
of crystal-field-splitting between two Ni- orbitals qualitatively affects
superconducting pairing symmetry of the bilayer two-orbital model, which
changes from to as the crystal-field-splitting exceeds a
critical value. When the model only includes nearest-neighbor and
second-nearest-neighbor hoppings, the crystal-field-splitting obtained by
fitting to the DFT band structure is larger than the critical value and thus
leads to superconducting pairing symmetry. When all nonzero
long-range-hoppings are also included in the model, the fitted
crystal-field-splitting is reduced and smaller than the critical value, which
makes superconducting pairing symmetry more favorable than
symmetry. Our work demonstrates that in downfolded effective models, the
details of band structure can play a crucial role in determining pairing
symmetry in multi-orbital unconventional superconductors (such as
LaNiO).Comment: 11 pages and 4 figure
Estimating moisture susceptibility of asphalt modified with alumina trihydrate
U radu je na temelju slobodne površinske energije, ocijenjena osjetljivost asfalta s aluminijevim trihidratom na vlagu. Analizirana su fizikalna svojstva i zapaljivost uzoraka s dodatkom aluminijeva trihidrata. Za potrebe istraživanja izrađeni su uzorci asfalta modificiranog stiren-butadien-stirenom s različitim udjelima ATH-a (0-14 %). Na uzorcima s dodatkom ATH-a analizirano je povećanje viskoznosti, točka razmekšanja, otpornost bitumena prema kolotraženju, granični indeks kisika i indeks penetracije. Iz aspekta mikromehanizama, ATH u velikoj mjeri nepovoljno utječe na oštećenje asfaltne mješavine uslijed djelovanja vlage.The moisture susceptibility of asphalt containing alumina trihydrate (ATH) was assessed through the surface free energy. Physical properties and flame retardancy of ATH samples were also investigated. For research purposes SBS modified asphalt samples with different dosages (0-14 %) of ATH were prepared. Increased viscosity, softening point limiting oxygen index and lower penetration ductility, were investigated for the ATH modified samples. ATH has a significant negative effect on the moisture-induced damage potential of asphalt mixture from the view of micromechanisms
ANALYSIS OF MULTI-CHANNEL TWO-DIMENSIONAL PROBABILITY CSMA AD HOC NETWORK PROTOCOL BASED THREE-WAY HANDSHAKE MECHANISM
In wireless Ad Hoc networks, large number and flexible mobility of terminals lead to the rarity of wireless channel resources. Also the hidden and exposed terminal problem exists in the Ad Hoc network which is the major factors restricting its development and applying. Considering these factors, this paper proposes a new CSMA protocol: multi-channel two-dimensional probability CSMA for wireless Ad Hoc network protocol based on three-way handshake mechanism, and analyzes the system throughput, delay of information packet, energy consumption and other properties under the control of the proposed protocol. By using the cycle analysis method, computer simulation results not only verify the theoretical analysis, but also show that the protocol has the optimum performance. The proposed protocol can not only reduce the collision probability of information packets to some extent, improving the channel utilization, reducing the waste of channel resources, but also achieve the balancing of load in a variety of wireless Ad Hoc network services, meeting the needs by different priorities with different QoS, and ensuring the systematic efficiency and fairness
An Improvement of Global Error Bound for the Generalized Nonlinear Complementarity Problem over a Polyhedral Cone
We consider the global error bound for the generalized nonlinear complementarity problem over a polyhedral cone (GNCP). By a new technique, we establish an easier computed global error bound for the GNCP under weaker conditions, which improves the result obtained by for GNCP
Atomic Ramsey interferometry with S- and D-band in a triangular optical lattice
Ramsey interferometers have wide applications in science and engineering.
Compared with the traditional interferometer based on internal states, the
interferometer with external quantum states has advantages in some applications
for quantum simulation and precision measurement. Here, we develop a Ramsey
interferometry with Bloch states in S- and D-band of a triangular optical
lattice for the first time. The key to realizing this interferometer in
two-dimensionally coupled lattice is that we use the shortcut method to
construct pulse. We observe clear Ramsey fringes and analyze the
decoherence mechanism of fringes. Further, we design an echo pulse
between S- and D-band, which significantly improves the coherence time. This
Ramsey interferometer in the dimensionally coupled lattice has potential
applications in the quantum simulations of topological physics, frustrated
effects, and motional qubits manipulation
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