5,477 research outputs found
Inequalities of Hermite-Hadamard type for extended -convex functions and applications to means
In the paper, the authors introduce a new concept "extended -convex
functions", establish some new integral inequalities of Hermite-Hadamard type
for this kind of functions, and apply these inequalities to derive some
inequalities of special means.Comment: 17 page
-Deformed Chern Characters for Quantum Groups
In this paper, we introduce an matrix in
the quantum groups to transform the conjugate representation into
the standard form so that we are able to compute the explicit forms of the
important quantities in the bicovariant differential calculus on ,
such as the -deformed structure constant and the
-deformed transposition operator . From the -gauge covariant
condition we define the generalized -deformed Killing form and the -th
-deformed Chern class for the quantum groups . Some
useful relations of the generalized -deformed Killing form are presented. In
terms of the -deformed homotopy operator we are able to compute the
-deformed Chern-Simons by the condition ,
Furthermore, the -deformed cocycle hierarchy, the -deformed gauge
covariant Lagrangian, and the -deformed Yang-Mills equation are derived
On the Capability of Measurement-Based Quantum Feedback
As a key method in dealing with uncertainties, feedback has been understood
fairly well in classical control theory. But for quantum control systems, the
capability of measurement-based feedback control (MFC) has not been
investigated systematically. In contrast to the control of classical systems
where the measurement effect is negligible, the quantum measurement will cause
a quantum state to collapse, which will inevitably introduce additional
uncertainties besides the system initial uncertainty. Therefore, there is a
complicated tradeoff between the uncertainty introduced and the information
gained by the measurement, and thus a theoretical investigation of the
capability of MFC is of fundamental importance. In this paper, inspired by both
the Heisenberg uncertainty principle for quantum systems and the investigation
of the feedback capability for classical systems, we try to answer the
following three basic questions: (i) How to choose the measurement channel
appropriately? (ii) Is the MFC still superior to the open loop control in
dealing with the system information uncertainties? and (iii) What is the
maximum capability or limitation of the MFC? These questions will be answered
theoretically by establishing several theorems concerning the asymptotic
reachability of eigenstates of a typical class of Hamiltonian control mode.Comment: 27 page
The modified Seiberg-Witten monopole equations and their exact solutions
The modified Seiberg-Witten monopole equations are presented in this letter.
These equations have analytic solutions in the whole 1+3 Minkowski space with
finite energy. The physical meaning of the equations and solutions are
discussed here.Comment: RevTex, 6 page, no figur
PPV modelling of memristor-based oscillator
In this letter, we propose for the first time a method of abstracting the PPV
(Perturbation Projection Vector) characteristic of the up-to-date
memristor-based oscillators. Inspired from biological oscillators and its
characteristic named PRC (Phase Response Curve), we build a bridge between PRC
and PPV. This relationship is verified rigorously using the transistor level
simulation of Colpitts and ring oscillators, i.e., comparing the PPV converted
from PRC and the PPV obtained from accurate PSS+PXF simulation. Then we apply
this method to the PPV calculation of the memristor-based oscillator. By
keeping the phase dynamics of the oscillator and dropping the details of
voltage/current amplitude, the PPV modelling is highly efficient to describe
the phase dynamics due to the oscillator coupling, and will be very suitable
for the fast simulation of large scale oscillatory neural networks
Enhancing Hydrogen Generation Through Nanoconfinement of Sensitizers and Catalysts in a Homogeneous Supramolecular Organic Framework.
Enrichment of molecular photosensitizers and catalysts in a confined nanospace is conducive for photocatalytic reactions due to improved photoexcited electron transfer from photosensitizers to catalysts. Herein, the self-assembly of a highly stable 3D supramolecular organic framework from a rigid bipyridine-derived tetrahedral monomer and cucurbit[8]uril in water, and its efficient and simultaneous intake of both [Ru(bpy)3 ]2+ -based photosensitizers and various polyoxometalates, that can take place at very low loading, are reported. The enrichment substantially increases the apparent concentration of both photosensitizer and catalyst in the interior of the framework, which leads to a recyclable, homogeneous, visible light-driven photocatalytic system with 110-fold increase of the turnover number for the hydrogen evolution reaction
Anderson localization in the Non-Hermitian Aubry-Andr\'e-Harper model with physical gain and loss
We investigate the Anderson localization in non-Hermitian
Aubry-Andr\'e-Harper (AAH) models with imaginary potentials added to lattice
sites to represent the physical gain and loss during the interacting processes
between the system and environment. By checking the mean inverse participation
ratio (MIPR) of the system, we find that different configurations of physical
gain and loss have very different impacts on the localization phase transition
in the system. In the case with balanced physical gain and loss added in an
alternate way to the lattice sites, the critical region (in the case with
p-wave superconducting pairing) and the critical value (both in the situations
with and without p-wave pairing) for the Anderson localization phase transition
will be significantly reduced, which implies an enhancement of the localization
process. However, if the system is divided into two parts with one of them
coupled to physical gain and the other coupled to the corresponding physical
loss, the transition process will be impacted only in a very mild way. Besides,
we also discuss the situations with imbalanced physical gain and loss and find
that the existence of random imaginary potentials in the system will also
affect the localization process while constant imaginary potentials will not.Comment: 6 pages, 4 figure
Generalized Aubry-Andr\'e-Harper model with p-wave superconducting pairing
We investigate a generalized Aubry-Andr\'e-Harper (AAH) model with p-wave
superconducting pairing. Both the hopping amplitudes between the nearest
neighboring lattice sites and the on-site potentials in this system are
modulated by a cosine function with a periodicity of . In the
incommensurate case [], due to the modulations on the
hopping amplitudes, the critical region of this quasiperiodic system is
significantly reduced and the system becomes more easily to be turned from
extended states to localized states. In the commensurate case (),
we find that this model shows three different phases when we tune the system
parameters: Su-Schrieffer-Heeger (SSH)-like trivial, SSH-like topological, and
Kitaev-like topological phases. The phase diagrams and the topological quantum
numbers for these phases are presented in this work. This generalized AAH model
combined with superconducting pairing provides us with a useful testfield for
studying the phase transitions from extended states to Anderson localized
states and the transitions between different topological phases.Comment: 9 pages, 5 figure
Quench dynamics in the Aubry-Andr\'e-Harper model with \textit{p}-wave superconductivity
The Anderson localization phase transition in the Aubry-Andr\'e-Harper (AAH)
model with \textit{p}-wave superconducting (SC) pairing is numerically
investigated by suddenly changing the on-site potential from zero to various
finite values which fall into the extended, critical and localized phase
regimes shown in this model. The time evolutions of entanglement entropy (EE),
mean width of wave packets and Loschmidt echo of the system exhibit distinct
but consistent dynamical signatures in those three phases. Specifically, the EE
grows as a power function of time with the exponent of which varies in the
extended phase but keeps almost unchanged in the critical phase for different
quench parameters. However, if the system is in the localized phase after a
quench, the EE grows much slower and will soon get saturated. The
time-dependent width of wave packets in the system shows similar behaviors as
the EE. In addition, from the perspective of dynamical phase transition, we
find that the Loschmidt echo oscillates and always keeps finite when the system
is quenched in the extended phase. In contrast, in the critical or localized
phase, the echo will reach to zero at some time intervals or will decay almost
to zero after a long-time evolution. The universal features of these quantities
in the critical phase of the system with various SC pairing amplitudes are also
observed.Comment: 9 pages, 6 figure
Quantum Clique Gossiping
This paper establishes a framework for the acceleration of quantum gossip
algorithms by introducing local clique operations to networks of interconnected
qubits. Cliques are local structures in complex networks being complete
subgraphs. Based on cyclic permutations, clique gossiping leads to collective
multi-party qubit interactions. This type of algorithm can be physically
realized by a series of local environments using coherent methods. First of
all, we show that at reduced states, these cliques have the same acceleration
effects as their roles in accelerating classical gossip algorithms, which can
even make possible finite-time convergence for suitable network structures.
Next, for randomized selection of cliques where node updates enjoy a more
self-organized and scalable sequencing, we show that the rate of convergence is
precisely improved by at the reduced states, where is
the size of the cliques and is the number of qubits in the network. The
rate of convergence at the coherent states of the overall quantum network is
proven to be decided by the spectrum of a mean-square error evolution matrix.
Explicit calculation of such matrix is rather challenging, nonetheless, the
effect of cliques on the coherent states' dynamics is illustrated via numerical
examples. Interestingly, the use of larger quantum cliques does not necessarily
increase the speed of the network density aggregation, suggesting quantum
network dynamics is not entirely decided by its classical topology.Comment: 12 pages, 2 figure
- …