24,867 research outputs found
Quantum Correction in Exact Quantization Rules
An exact quantization rule for the Schr\"{o}dinger equation is presented. In
the exact quantization rule, in addition to , there is an integral term,
called the quantum correction. For the exactly solvable systems we find that
the quantum correction is an invariant, independent of the number of nodes in
the wave function. In those systems, the energy levels of all the bound states
can be easily calculated from the exact quantization rule and the solution for
the ground state, which can be obtained by solving the Riccati equation. With
this new method, we re-calculate the energy levels for the one-dimensional
systems with a finite square well, with the Morse potential, with the symmetric
and asymmetric Rosen-Morse potentials, and with the first and the second
P\"{o}schl-Teller potentials, for the harmonic oscillators both in one
dimension and in three dimensions, and for the hydrogen atom.Comment: 10 pages, no figure, Revte
Centrality, system size and energy dependences of charged-particle pseudo-rapidity distribution
Utilizing the three-fireball picture within the quark combination model, we
study systematically the charged particle pseudorapidity distributions in both
Au+Au and Cu+Cu collision systems as a function of collision centrality and
energy, 19.6, 62.4, 130 and 200 GeV, in full pseudorapidity
range. We find that: (i)the contribution from leading particles to
distributions increases with the decrease of the collision
centrality and energy respectively; (ii)the number of the leading particles is
almost independent of the collision energy, but it does depend on the nucleon
participants ; (iii)if Cu+Cu and Au+Au collisions at the same
collision energy are selected to have the same , the resulting of
charged particle distributions are nearly identical, both in the
mid-rapidity particle density and the width of the distribution. This is true
for both 62.4 GeV and 200 GeV data. (iv)the limiting fragmentation phenomenon
is reproduced. (iiv) we predict the total multiplicity and pseudorapidity
distribution for the charged particles in Pb+Pb collisions at TeV. Finally, we give a qualitative analysis of the
and as function of
and from RHIC to LHC.Comment: 12 pages, 8 figure
A Non-equilibrium STM model for Kondo Resonance on surface
Based on a no-equilibrium STM model, we study Kondo resonance on a surface by
self-consistent calculations. The shapes of tunneling spectra are dependent on
the energy range of tunneling electrons. Our results show that both
energy-cutoff and energy-window of tunneling electrons have significant
influence on the shapes of tunneling spectra. If no energy-cutoff is used, the
Kondo resonances in tunneling spectrum are peaks with the same shapes in the
density of state of absorbed magnetic atoms. This is just the prediction of
Tersoff theory. If we use an energy cutoff to remove high-energy lectrons, a
dip structure will modulate the Kondo resonance peak in the tunneling spectrum.
The real shape of Kondo peak is the mixing of the peak and dip, the so-called
Fano line shape. The method of self-consistent non-equilibrium matrix Green
function is discussed in details.Comment: 11 pages and 8 eps figur
Onset of unsteady horizontal convection in rectangle tank at
The horizontal convection within a rectangle tank is numerically simulated.
The flow is found to be unsteady at high Rayleigh numbers. There is a Hopf
bifurcation of from steady solutions to periodic solutions, and the
critical Rayleigh number is obtained as for the
middle plume forcing at , which is much larger than the formerly obtained
value. Besides, the unstable perturbations are always generated from the
central jet, which implies that the onset of instability is due to velocity
shear (shear instability) other than thermally dynamics (thermal instability).
Finally, Paparella and Young's [J. Fluid Mech. 466 (2002) 205] first hypotheses
about the destabilization of the flow is numerically proved, i.e. the middle
plume forcing can lead to a destabilization of the flow.Comment: 4pages, 6 figures, extension of Chin. Phys. Lett. 2008, 25(6), in
pres
Quantum limited particle sensing in optical tweezers
Particle sensing in optical tweezers systems provides information on the
position, velocity and force of the specimen particles. The conventional
quadrant detection scheme is applied ubiquitously in optical tweezers
experiments to quantify these parameters. In this paper we show that quadrant
detection is non-optimal for particle sensing in optical tweezers and propose
an alternative optimal particle sensing scheme based on spatial homodyne
detection. A formalism for particle sensing in terms of transverse spatial
modes is developed and numerical simulations of the efficacy of both quadrant
and spatial homodyne detection are shown. We demonstrate that an order of
magnitude improvement in particle sensing sensitivity can be achieved using
spatial homodyne over quadrant detection.Comment: Submitted to Biophys
Evidence for a Quantum Hall Insulator in an InGaAs/InP Heterostructure
We study the quantum critical behavior of the plateau-insulator (PI)
transition in a low mobility InGaAs/InP heterostructure. By reversing the
direction of the magnetic field (B) we find an averaged Hall resistance \rho_xy
which remains quantized at the plateau value h/e^2 throughout the PI
transition. We extract a critical exponent \kappa'= 0.57 +/- 0.02 for the PI
transition which is slightly different from (and possibly more accurate than)
the established value 0.42 +/- 0.04 as previously obtained from the
plateau-plateau (PP) transitions.Comment: 3pages, 2 figures; submitted to EP2DS-14 conference proceeding
Parameterizing Majorana Neutrino Couplings in the Higgs Sector
Nonzero masses for the active neutrinos - regardless of their nature or
origin - arise only after electroweak symmetry breaking. We discuss the
parameterization of neutrino couplings to a Higgs sector consisting of one
SU(2)_L scalar doublet and one SU(2)_L scalar triplet, and allow for
right-handed neutrinos whose Majorana mass parameters arise from the vacuum
expectation value of a Standard Model scalar singlet. If the neutrinos are
Majorana fermions, all Yukawa couplings can be expressed as functions of the
neutrino mass eigenvalues and a subset of the elements of the neutrino mixing
matrix. In the mass basis, the Yukawa couplings are, in general, not diagonal.
This is to be contrasted to the case of charged-fermions or Dirac neutrinos,
where couplings to the Higgs-boson are diagonal in the mass basis and
proportional only to the fermion masses. Nonetheless, all physically
distinguishable parameters can be reached if all neutrino masses are
constrained to be positive, all mixing angles constrained to lie in the first
quadrant (theta in [0,pi/2]), and all Majorana phases to lie in the first two
quadrants (phi in [0,pi]), as long as all Dirac phases vary within the entire
unit circle (delta in [0,2pi}). We discuss several concrete examples and
comment on the Casas-Ibarra parameterization for the neutrino Yukawa couplings
in the case of the type-I Seesaw Lagrangian.Comment: 13 pages, 2 eps figure
Mandate-driven networking eco-system : a paradigm shift in end-to-end communications
The wireless industry is driven by key stakeholders that follow a holistic approach of "one-system-fits-all" that leads to moving network functionality of meeting stringent End-to-End (E2E) communication requirements towards the core and cloud infrastructures. This trend is limiting smaller and new players for bringing in new and novel solutions. For meeting these E2E requirements, tenants and end-users need to be active players for bringing their needs and innovations. Driving E2E communication not only in terms of quality of service (QoS) but also overall carbon footprint and spectrum efficiency from one specific community may lead to undesirable simplifications and a higher level of abstraction of other network segments may lead to sub-optimal operations. Based on this, the paper presents a paradigm shift that will enlarge the role of wireless innovation at academia, Small and Medium-sized Enterprises (SME)'s, industries and start-ups while taking into account decentralized mandate-driven intelligence in E2E communications
Mapping quantum geometry and quantum phase transitions to real space by a fidelity marker
The quantum geometry in the momentum space of semiconductors and insulators,
described by the quantum metric of the valence band Bloch state, has been an
intriguing issue owing to its connection to various material properties.
Because the Brillouin zone is periodic, the integration of quantum metric over
momentum space represents an average distance between neighboring Bloch states,
of which we call the fidelity number. We show that this number can further be
expressed in real space as a fidelity marker, which is a local quantity that
can be calculated directly from diagonalizing the lattice Hamiltonian. A linear
response theory is further introduced to generalize the fidelity number and
marker to finite temperature, and moreover demonstrates that they can be
measured from the global and local optical absorption power against linearly
polarized light. In particular, the fidelity number spectral function in 2D
systems can be easily measured from the opacity of the material. Based on the
divergence of quantum metric, a nonlocal fidelity marker is further introduced
and postulated as a universal indicator of any quantum phase transitions
provided the crystalline momentum remains a good quantum number, and it may be
interpreted as a Wannier state correlation function. The ubiquity of these
concepts is demonstrated for a variety of topological insulators and
topological phase transitions in different dimensions.Comment: 11 pages, 5 figure
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