6,837 research outputs found
Statistical Properties of E(5) and X(5) Symmetries
We study the energy level statistics of the states in E(5) and X(5)
transitional dynamical symmetries. The calculated results indicate that the
statistics of E(5) symmetry is regular and follows Poisson statistics, while
the statistics of X(5) symmetry involves two maxima in the nearest neighbor
level spacing distribution and the statistics follows the
GOE statistics. It provides an evidence that the X(5) symmetry is at the
critical point exhibiting competing degree of freedom.Comment: 15 pages, 14 figure
Quantum Information Transfer between Topological and Superconducting Qubits
We describe a scheme that enables a strong Jaynes-Cummings coupling between a
topological qubit and a superconducting flux qubit. The coupling strength is
dependent on the phase difference between two superconductors on a topological
insulator and may be expediently controlled by a phase controller. With this
coherent coupling and single-qubit rotations arbitrary unitary operations on
the two-qubit hybrid system of topological and flux qubits can be performed.
Numerical simulations show that quantum state transfer and entanglement
distributing between the topological and superconducting flux qubits may be
performed with high fidelity.Comment: 5 pages, 3 figure
Electrical Control of Strong Spin-Phonon Coupling in a Carbon Nanotube
We describe an approach to electrically control the strong interaction
between a single electron spin and the vibrational motion of a suspended carbon
nanotube resonator. The strength of the deflection-induced spin-phonon coupling
is dependent on the wavefunction of the electron confined in a lateral carbon
nanotube quantum dot. An electrical field along the nanotube shifts the
effective center of the quantum dot, leading to the corresponding modification
of the spin-phonon strength. Numerical simulations with experimentally
reachable parameters show that high fidelity quantum state transfer between
mechanical and spin qubits driven by electrical pulses is feasible. Our results
form the basis for the fully electrical control of the coherent interconvertion
between light and spin qubits and for manufacturing electrically driven quantum
information processing systems.Comment: 4pages,3figure
Lie-point symmetries of the Lagrangian system on time scales
This letter investigates the Lie point symmetries and conserved quantities of
the Lagrangian systems on time scales, which unify the Lie symmetries of the
two cases for the continuous and the discrete Lagrangian systems. By defining
the infinitesimal transformations' generators and using the invariance of
differential equations under infinitesimal transformations, the determining
equations of the Lie symmetries on time scales are established. Then the
structure equations and the form of conserved quantities with delta derivatives
are obtained. The letter also gives brief discussion on the Lie symmetries for
the discrete systems. Finally, several examples are designed to illustrate
these results.Comment: 14 pages,0 figure
Two-particle interferometry for the sources undergoing first-order QCD phase transition in high energy heavy ion collisions
We investigate the two-particle interferometry for the particle-emitting
sources which undergo the first-order phase transition from the quark-gluon
plasma with a finite baryon chemical potential to hadron resonance gas. The
effects of source expansion, lifetime, and particle absorption on the
transverse interferometry radii and are examined.
We find that the emission durations of the particles become large when the
system is initially located at the boundary between the mixed phase and the
quark-gluon plasma. In this case, the difference between the radii and increases with the transverse momentum of the particle
pair significantly. The ratio of to the
transverse velocity of the pair is an observable for the enhancement of the
emission duration.Comment: 10 pages, 12 figures. arXiv admin note: text overlap with
arXiv:0811.475
Pseudo-rapidity Distributions of Charged Hadrons in pp and pA Collisions at the LHC
In the framework of Color Glass Condensate, the pseudo-rapidity distributions
of charged hadrons in pp and pA collisions at the LHC are studied with the UGD
function from the GBW model. With a analysis of the CMS data in pp
collisions at TeV, the normalization factor is obtained
and the theoretical results are in good agreement with the perimental data.
Then, considering the influence of nucleon hard partons distribution on the
number of participants in pA collisions by a Glauber Monte Carlo method, we
give the predictive results for the multiplicity distributions in p+Pb
collisions at TeV.Comment: 9 pages, 3 figure
A holographic model of d-wave superconductor vortices with Lifshitz scaling
We study analytically the -wave holographic superconductors with Lifshitz
scaling in the presence of external magnetic field. The vortex lattice
solutions of the model have also been obtained with different Lifshitz scaling.
Our results imply that holographic -wave superconductor is indeed a type II
one even for different Lifshitz scaling. This is the same as the conventional
-wave superconductors in the Ginzburg-Landau theory.
Our results also indicate that the dynamical exponent has no effect to
the shape of the vortex lattice even after higher order corrections (away from
the phase transition point ) are included. However, it has effects on the
upper critical magnetic field through the fact that a larger
results in a smaller and therefore influences the size (characterized
by ) of the vortex lattices. Furthermore, close
comparisons between our results and those of the Ginzburg-Landau theory reveal
the fact that the upper critical magnetic field is inversely
proportional to the square of the superconducting coherence length ,
regardless of the anisotropy between space and time.Comment: 21 pages, 6 figures. One subsection added, typos corrected,
references added. arXiv admin note: substantial text overlap with
arXiv:1311.6260, arXiv:1209.4272, arXiv:1007.4151 by other author
Hierarchical modularity of nested bow-ties in metabolic networks
The exploration of the structural topology and the organizing principles of
genome-based large-scale metabolic networks is essential for studying possible
relations between structure and functionality of metabolic networks.
Topological analysis of graph models has often been applied to study the
structural characteristics of complex metabolic networks.In this work,
metabolic networks of 75 organisms were investigated from a topological point
of view. Network decomposition of three microbes (Escherichia coli, Aeropyrum
pernix and Saccharomyces cerevisiae) shows that almost all of the sub-networks
exhibit a highly modularized bow-tie topological pattern similar to that of the
global metabolic networks. Moreover, these small bow-ties are hierarchically
nested into larger ones and collectively integrated into a large metabolic
network, and important features of this modularity are not observed in the
random shuffled network. In addition, such a bow-tie pattern appears to be
present in certain chemically isolated functional modules and spatially
separated modules including carbohydrate metabolism, cytosol and mitochondrion
respectively. The highly modularized bow-tie pattern is present at different
levels and scales, and in different chemical and spatial modules of metabolic
networks, which is likely the result of the evolutionary process rather than a
random accident. Identification and analysis of such a pattern is helpful for
understanding the design principles and facilitate the modelling of metabolic
networks.Comment: 26 pages, 9 figure
Bow-tie topological features of metabolic networks and the functional significance
Exploring the structural topology of genome-based large-scale metabolic
network is essential for investigating possible relations between structure and
functionality. Visualization would be helpful for obtaining immediate
information about structural organization. In this work, metabolic networks of
75 organisms were investigated from a topological point of view. A spread
bow-tie model was proposed to give a clear visualization of the bow-tie
structure for metabolic networks. The revealed topological pattern helps to
design more efficient algorithm specifically for metabolic networks. This
coarse-grained graph also visualizes the vulnerable connections in the network,
and thus could have important implication for disease studies and drug target
identifications. In addition, analysis on the reciprocal links and main cores
in the GSC part of bow-tie also reveals that the bow-tie structure of metabolic
networks has its own intrinsic and significant features which are significantly
different from those of random networks.Comment: 15 pages, 5 figure
Strong Coupling between a Topological Qubit and a Nanomechanical Resonator
We describe a scheme that enables a strong coherent coupling between a
topological qubit and the quantized motion of a magnetized nanomechanical
resonator. This coupling is achieved by attaching an array of magnetic tips to
a namomechanical resonator under a quantum phase controller which coherently
controls the energy gap of a topological qubit. Combined with single-qubit
rotations the strong coupling enables arbitrary unitary transformations on the
hybrid system of topological and mechanical qubits and may pave the way for the
quantum information transfer between topological and optical qubits. Numerical
simulations show that quantum state transfer and entanglement distributing
between the topological and mechanical qubits may be accomplished with high
fidelity.Comment: 5 pages, 3 figures. arXiv admin note: text overlap with
arXiv:1301.453
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