112,866 research outputs found
Pairing symmetry of heavy fermion superconductivity in the two-dimensional Kondo-Heisenberg lattice model
In the two-dimensional Kondo-Heisenberg lattice model away from half-filled,
the local antiferromagnetic exchange coupling can provide the pairing mechanism
of quasiparticles via the Kondo screening effect, leading to the heavy fermion
superconductivity. We find that the pairing symmetry \textit{strongly} depends
on the Fermi surface (FS) structure in the normal metallic state. When
is very small, the FS is a small hole-like circle around the
corner of the Brillouin zone, and the s-wave pairing symmetry has a lower
ground state energy. For the intermediate coupling values of , the
extended s-wave pairing symmetry gives the favored ground state. However, when
is larger than a critical value, the FS transforms into four
small hole pockets crossing the boundary of the magnetic Brillouin zone, and
the d-wave pairing symmetry becomes more favorable. In that regime, the
resulting superconducting state is characterized by either nodal d-wave or
nodeless d-wave state, depending on the conduction electron filling factor as
well. A continuous phase transition exists between these two states. This
result may be related to the phase transition of the nodal d-wave state to a
fully gapped state, which is recently observed in Yb doped CeCoIn.Comment: 5 pages, 5 figures; published versio
Equivalent Effect Function and Fast Intrinsic Mode Decomposition
The Equivalent Effect Function (EEF) is defined as having the identical
integral values on the control points of the original time series data; the EEF
can be obtained from the derivative of the spline function passing through the
integral values on the control points. By choosing control points with
different criteria, the EEF can be used to find the intrinsic mode
function(IMF, fluctuation) and the residue (trend); to fit the curve of the
original data function; and to take samples on original data with equivalent
effect. As examples of application, results of trend and fluctuation on real
stock historical data are calculated on different time scales. A new approach
to extend the EEF to 2D intrinsic mode decomposition is introduced to resolve
the inter slice non continuity problem, some photo image decomposition examples
are presented
Number Statistics of Ultracold Bosons in Optical Lattice
We study the number statistics of ultracold bosons in optical Lattice using
the slave particle technique and quantum Monte Carlo simulations. For
homogeneous Bose-Hubbard model, we use the slave particle technique to obtain
the number statistics near the superfluid to normal-liquid phase transition.
The qualitatively behavior agree with the recent experiment probing number
fluctuation [Phys. Rev. Lett. \textbf{96}, 090401 (2006)]. We also perform
quantum Monte Carlo simulations to 1D system with external harmonic trap. The
results qualitatively agree with the experiments.Comment: 5 pages, 4 figure
Weak ferromagnetism with the Kondo screening effect in the Kondo lattice systems
We carefully consider the interplay between ferromagnetism and the Kondo
screening effect in the conventional Kondo lattice systems at finite
temperatures. Within an effective mean-field theory for small conduction
electron densities, a complete phase diagram has been determined. In the
ferromagnetic ordered phase, there is a characteristic temperature scale to
indicate the presence of the Kondo screening effect. We further find two
distinct ferromagnetic long-range ordered phases coexisting with the Kondo
screening effect: spin fully polarized and partially polarized states. A
continuous phase transition exists to separate the partially polarized
ferromagnetic ordered phase from the paramagnetic heavy Fermi liquid phase.
These results may be used to explain the weak ferromagnetism observed recently
in the Kondo lattice materials.Comment: 6 pages, 6 figures; published versio
Phase evolution of the two-dimensional Kondo lattice model near half-filling
Within a mean-field approximation, the ground state and finite temperature
phase diagrams of the two-dimensional Kondo lattice model have been carefully
studied as functions of the Kondo coupling and the conduction electron
concentration . In addition to the conventional hybridization between
local moments and itinerant electrons, a staggered hybridization is proposed to
characterize the interplay between the antiferromagnetism and the Kondo
screening effect. As a result, a heavy fermion antiferromagnetic phase is
obtained and separated from the pure antiferromagnetic ordered phase by a
first-order Lifshitz phase transition, while a continuous phase transition
exists between the heavy fermion antiferromagnetic phase and the Kondo
paramagnetic phase. We have developed a efficient theory to calculate these
phase boundaries. As decreases from the half-filling, the region of the
heavy fermion antiferromagnetic phase shrinks and finally disappears at a
critical point , leaving a first-order critical line between
the pure antiferromagnetic phase and the Kondo paramagnetic phase for
. At half-filling limit, a finite temperature phase diagram
is also determined on the Kondo coupling and temperature (-) plane.
Notably, as the temperature is increased, the region of the heavy fermion
antiferromagnetic phase is reduced continuously, and finally converges to a
single point, together with the pure antiferromagnetic phase and the Kondo
paramagnetic phase. The phase diagrams with such triple point may account for
the observed phase transitions in related heavy fermion materials.Comment: 9 pages, 9 figure
A mixed clustering coefficient centrality for identifying essential proteins
Essential protein plays a crucial role in the process of cell life. The
identification of essential proteins can not only promote the development of
drug target technology, but also contribute to the mechanism of biological
evolution. There are plenty of scholars who pay attention to discovering
essential proteins according to the topological structure of protein network
and biological information. The accuracy of protein recognition still demands
to be improved. In this paper, we propose a method which integrate the
clustering coefficient in protein complexes and topological properties to
determine the essentiality of proteins. First, we give the definition of
In-clustering coefficient (IC) to describe the properties of protein complexes.
Then we propose a new method, complex edge and node clustering coefficient
(CENC) to identify essential proteins. Different Protein-Protein Interaction
(PPI) networks of Saccharomyces cerevisiae, MIPS and DIP are used as
experimental materials. Through some experiments of logistic regression model,
the results show that the method of CENC can promote the ability of recognizing
essential proteins, by comparing with the existing methods DC, BC, EC, SC, LAC,
NC and the recent method UC.Comment: arXiv admin note: substantial text overlap with arXiv:2003.0358
Stealthy Malware Traffic - Not as Innocent as It Looks
Malware is constantly evolving. Although existing countermeasures have
success in malware detection, corresponding counter-countermeasures are always
emerging. In this study, a counter-countermeasure that avoids network-based
detection approaches by camouflaging malicious traffic as an innocuous protocol
is presented. The approach includes two steps: Traffic format transformation
and side-channel massage (SCM). Format transforming encryption (FTE) translates
protocol syntax to mimic another innocuous protocol while SCM obscures traffic
side-channels. The proposed approach is illustrated by transforming Zeus botnet
(Zbot) Command and Control (C&C) traffic into smart grid Phasor Measurement
Unit (PMU) data. The experimental results show that the transformed traffic is
identified by Wireshark as synchrophasor protocol, and the transformed protocol
fools current side-channel attacks. Moreover, it is shown that a real smart
grid Phasor Data Concentrator (PDC) accepts the false PMU data.Comment: 9 figures, 2 table
Hull Form Optimization with Principal Component Analysis and Deep Neural Network
Designing and modifying complex hull forms for optimal vessel performances
have been a major challenge for naval architects. In the present study,
Principal Component Analysis (PCA) is introduced to compress the geometric
representation of a group of existing vessels, and the resulting principal
scores are manipulated to generate a large number of derived hull forms, which
are evaluated computationally for their calm-water performances. The results
are subsequently used to train a Deep Neural Network (DNN) to accurately
establish the relation between different hull forms and their associated
performances. Then, based on the fast, parallel DNN-based hull-form evaluation,
the large-scale search for optimal hull forms is performed.Comment: 20 page
Magnetic field effects on two-leg Heisenberg antiferromagnetic ladders: Thermodynamic properties
Using the recently developed transfer-matrix renormalization group method, we
have studied the thermodynamic properties of two-leg antiferromagnetic ladders
in the magnetic field. Based on different behavior of magnetization, we found
disordered spin liquid, Luttinger liquid, spin-polarized phases and a classical
regime depending on magnetic field and temperature. Our calculations in
Luttinger liquid regime suggest that both the divergence of the NMR relaxation
rate and the anomalous specific heat behavior observed on
Cu(CHN)Cl}are due to quasi-one-dimensional effect
rather than three-dimensional ordering.Comment: 4 pages and 6 figures; some parts of the text has been revised in
this version accepted by Phys. Rev. Let
Tensorization of the strong data processing inequality for quantum chi-square divergences
It is well-known that any quantum channel satisfies the data
processing inequality (DPI), with respect to various divergences, e.g., quantum
divergences and quantum relative entropy. More specifically,
the data processing inequality states that the divergence between two arbitrary
quantum states and does not increase under the action of any
quantum channel . For a fixed channel and a state
, the divergence between output states and
might be strictly smaller than the divergence between
input states and , which is characterized by the strong data
processing inequality (SDPI). Among various input states , the largest
value of the rate of contraction is known as the SDPI constant. An important
and widely studied property for classical channels is that SDPI constants
tensorize. In this paper, we extend the tensorization property to the quantum
regime: we establish the tensorization of SDPIs for the quantum
divergence for arbitrary quantum channels and also for
a family of divergences (with ) for
arbitrary quantum-classical channels.Comment: Accepted by Quantu
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