16,126 research outputs found
Single-particle subband structure of Quantum Cables
We proposed a model of Quantum Cable in analogy to the recently synthesized
coaxial nanocable structure [Suenaga et al. Science, 278, 653 (1997); Zhang et
al. ibid, 281, 973 (1998)], and studied its single-electron subband structure.
Our results show that the subband spectrum of Quantum Cable is different from
either double-quantum-wire (DQW) structure in two-dimensional electron gas
(2DEG) or single quantum cylinder. Besides the double degeneracy of subbands
arisen from the non-abelian mirrow reflection symmetry, interesting
quasicrossings (accidental degeneracies), anticrossings and bundlings of
Quantum Cable energy subbands are observed for some structure parameters. In
the extreme limit (barrier width tends to infinity), the normal degeneracy of
subbands different from the DQW structure is independent on the other structure
parameters.Comment: 12 pages, 9 figure
Quantum Cable as transport spectroscopy of 1D DOS of cylindrical quantum wires
We considered the proposed Quantum Cable as a kind of transport spectroscopy
of one-dimensional (1D) density of states (DOS) of cylindrical quantum wires.
By simultaneously detecting the direct current through the cylindrical quantum
wire and the leaked tunneling current into the neighboring wire at desired
temperatures, one can obtain detailed information about 1D DOS and subband
structure of cylindrical quantum wires.Comment: 7 pages, 4 figures, late
Ballistic electronic transport in Quantum Cables
We studied theoretically ballistic electronic transport in a proposed
mesoscopic structure - Quantum Cable. Our results demonstrated that Qauntum
Cable is a unique structure for the study of mesoscopic transport. As a
function of Fermi energy, Ballistic conductance exhibits interesting stepwise
features. Besides the steps of one or two quantum conductance units (),
conductance plateaus of more than two quantum conductance units can also be
expected due to the accidental degeneracies (crossings) of subbands. As
structure parameters is varied, conductance width displays oscillatory
properties arising from the inhomogeneous variation of energy difference
betweeen adjoining transverse subbands. In the weak coupling limits,
conductance steps of height becomes the first and second plateaus for
the Quantum Cable of two cylinder wires with the same width.Comment: 11 pages, 5 figure
Effect of bilayer coupling on tunneling conductance of double-layer high T_c cuprates
Physical effects of bilayer coupling on the tunneling spectroscopy of high
T cuprates are investigated. The bilayer coupling separates the bonding
and antibonding bands and leads to a splitting of the coherence peaks in the
tunneling differential conductance. However, the coherence peak of the bonding
band is strongly suppressed and broadened by the particle-hole asymmetry in the
density of states and finite quasiparticle life-time, and is difficult to
resolve by experiments. This gives a qualitative account why the bilayer
splitting of the coherence peaks was not clearly observed in tunneling
measurements of double-layer high-T oxides.Comment: 4 pages, 3 figures, to be published in PR
On exploiting priority relation graph for reliable multi-path communication in mobile social networks
© 2018 Elsevier Inc. A mobile social network (MSN) consists of certain amount of mobile users with social characteristics, and it provides data delivery concerning social relationships between mobile users. In MSN, ordinary people contact each other more frequently if they have more social features in common. In this paper, we apply a new topology structure–priority relation graph (PRG) to evaluate the data delivery routing in MSN on the system-level. By using the natural order of nodes’ representation, the diameter, the regular degree and the multi-path technology, we determine the priority relation graph-based social feature routing (PRG-SFR) algorithm to find disjointed multi-paths in MSN. Here, the multi-path technology can be exploited for ensuring that, between each pair of sender and receiver, the important information can be delivered through a highly reliable path. Then we calculate the tolerant ability of ‘faults’ and estimate the availability of MSN on the theoretical level. Finally, we analyze the efficiency of PRG-SFR algorithm from the numerical standpoint in terms of fault tolerance, forwarding number, transmission time and delivery rate. Moreover, we make comparisons between PRG-SFR algorithm and certain state-of-the-art technologies
Quantum transfer matrix method for one-dimensional disordered electronic systems
We develop a novel quantum transfer matrix method to study thermodynamic
properties of one-dimensional (1D) disordered electronic systems. It is shown
that the partition function can be expressed as a product of local
transfer matrices. We demonstrate this method by applying it to the 1D
disordered Anderson model. Thermodynamic quantities of this model are
calculated and discussed.Comment: 7 pages, 10 figure
Entanglement-enhanced measurement of a completely unknown phase
The high-precision interferometric measurement of an unknown phase is the
basis for metrology in many areas of science and technology. Quantum
entanglement provides an increase in sensitivity, but present techniques have
only surpassed the limits of classical interferometry for the measurement of
small variations about a known phase. Here we introduce a technique that
combines entangled states with an adaptive algorithm to precisely estimate a
completely unspecified phase, obtaining more information per photon that is
possible classically. We use the technique to make the first ab initio
entanglement-enhanced optical phase measurement. This approach will enable
rapid, precise determination of unknown phase shifts using interferometry.Comment: 6 pages, 4 figure
- …