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Shun-Jin Wang

Publications and source records attributed to Shun-Jin Wang.

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Microscopic quantum structure of black hole and vacuum versus quantum statistical origin of gravity

The Planckon densely piled model of vacuum is proposed. Based on this model, the microscopic quantum structure of Schwarzschild black hole and quantum statistical origin of its gravity are studied. The cutoff of black hole horizon leads to Casimir effect inside the horizon. This effect makes the inside vacuum has less zero quantum fluctuation energy than that of outside vacuum and the spin 1/2 radiation hole excitations are resulted inside the horizon. The mean energy of the radiation hole excitations is related to the temperature decrease of the Hawking-Unruh type by the period law of the Fermion temperature greens function and a temperature difference as well as gravity are created on the horizon. A dual relation of the gravity potentials between inside and outside regions of the black hole is found. An attractor behaviour of the horizon surface is unveiled. The gravity potential inside the black hole is linear in radial coordinate and no singularity exists at the origin of the black hole, in contrast to the conventional conjecture. All the particles absorbed by the black hole have fallen down to the horizon and converted into spin 1/2 radiation quanta with the mean energy related to the Hawking-Unruh temperature, the thermodynamic equilibrium and the mechanical balance make the radiation quanta be tightly bound in the horizon. The gravitation mass $2M$ and physical mass $M$ of the black hole are calculated. The calculated entropy of the black hole is well consistent with Hawking. Outside the horizon, there exist thermodynamic non-equilibrium and mechanical non-balance which lead to an outward centrifugal energy flow and an inward gravitation energy flow. The lost vacuum energy in the negative gravitation potential region has been removed to the black hole surface to form a spherical Planckon shell with the thickness of Planckon diameter so that energy conservation is guaranteed.

physics.gen-ph

Vacuum quantum fluctuation energy in expanding universe and dark energy

This article is based on the Planckon densely piled vacuum model and the principle of cosmology. With the Planck era as initial conditions and including the early inflation, we have solved the Einstein-Friedmann equations to describe the evolution of the universe. The results are: 1) the ratio of the dark energy density to the vacuum quantum fluctuation energy density is $\frac{{{ρ}_{de}}}{{{ρ}_{vac}}}\sim{{(\frac{{{t}_{P}}}{{{T}_{0}}})}^{2}}\sim{{10}^{-122}} $; 2) at the inflation time ${{t}_{\inf }}={{10}^{-35}}s$, the calculated universe radiation energy density is $ρ({{t}_{\inf }})\sim{{10}^{-16}}{{ρ}_{vac}}$ and the corresponding temperature is ${{E}_{c}}\sim{{10}^{15}}GeV$ consistent with the GUT phase transition temperature; 3) the expanding universe with vacuum as its environment is a non-equilibrium open system constantly exchanging energy with vacuum; during its expansion, the Planckons in the universe lose quantum fluctuation energy and create the cosmic expansion quanta-cosmons, the energy of cosmons is the lost part of the vacuum quantum fluctuation energy and contributes to the universe energy with the calculated value ${{E}_{\cos mos}}={{10}^{22}}{{M}_{\otimes }}{{c}^{2}}$ (where ${{M}_{\otimes }}$ is solar mass); 4) the total energy of the universe, namely the negative gravity energy plus the positive universe energy is zero; 5) the negative gravity potential and the gravity acceleration related to the creation of cosmons are derived with the nature of outward repulsive force, indicating that the cosmon may be the candidate of the dark energy quantum; 6) both the initial Planck era solution and the infinite asymptotic solution of the Einstein-Friedman equations are unstable: the former tends to expand and the latter tends to shrink, so that the Einstein-Friedman universe will undergo a cyclic evolution of successive expansion and shrinking.

physics.gen-ph

QCD inspired relativistic bound state model and meson structures

A QCD inspired relativistic effective Hamiltonian model for the bound states of mesons has been constructed, which integrates the advantages of several QCD effective Hamiltonian models. Based on light-front QCD effective Hamiltonian model, the squared invariant mass operator of meson is used as the effective Hamiltonian. The model has been improved significantly in four major aspects: i)it is proved that in center of mass frame and in internal coordinate Hilbert subspace, the total angular momentum $J$ of meson is conserved and the mass eigen equation can be expressed in total angular momentum representation and in terms of a set of coupled radial eigen equations for each $J$. ii)Based on lattice QCD results, a relativistic confining potential is introduced into the effective interaction and the excited states of mesons can be well described. iii)an SU(3) flavor mixing interaction is introduced phenomenologically to describe the flavor mixing mesons and the mass eigen equations contain the coupling among different flavor components. iv)the mass eigen equations are of relativistic covariance and the coupled radial mass eigen equations take full account of $L-S $ coupling and tensor interactions. The model has been applied to describe the whole meson spectra of about 265 mesons with available data. The agreement of the calculated masses, squared radii, and decay constants with data is quite well. For the mesons whose mass data have large experimental uncertainty, the model produces certain mass values for test. For some mesons whose total angular momenta and parity are not assigned experimentally, the model gives a prediction of the spectroscopic configuration$^{2S+1}L_J$. The connection between our model and the recent low energy QCD issues-the infrared conformal scaling invariance and holographic QCD hadron models is discussed.

hep-th

Entanglement dynamics of qubits in a common environment

We use the quantum jump approach to study the entanglement dynamics of a quantum register, which is composed of two or three dipole-dipole coupled two-level atoms, interacting with a common environment. Our investigation of entanglement dynamics reflects that the environment has dual actions on the entanglement of the qubits in the model. While the environment destroys the entanglement induced by the coherent dipole-dipole interactions, it can produce stable entanglement between the qubits prepared initially in a separable state. The analysis shows that it is the entangled decoherence-free states contained as components in the initial state that contribute to the stable entanglement. Our study indicates how the environmental noise produces the entanglement and exposes the interplay of environmental noise and coherent interactions of qubits on the entanglement.

quant-ph

On the super-fluid property of the relativistic physical vacuum medium and the inertial motion of particles

The similarity between the energy spectra of relativistic particles and that of quasi-particles in super-conductivity BCS theory makes us conjecture that the relativistic physical vacuum medium as the ground state of the background field is a super fluid medium, and the rest mass of a relativistic particle is like the energy gap of a quasi-particle. This conjecture is strongly supported by the results of our following investigation: a particle moving through the vacuum medium at a speed less than the speed of light in vacuum, though interacting with the vacuum medium, never feels friction force and thus undergoes a frictionless and inertial motion. The profound and intrinsic relationship between the super fluid property of the relativistic physical vacuum medium and the energy-momentum conservation law as well as the relativistic energy-momentum dispersion relation or the principle of relativity, can be established.

gr-qc

Entanglement production and decoherence-free subspace of two single-mode cavities embedded in a common environment

A system consisting of two identical single-mode cavities coupled to a common environment is investigated within the framework of algebraic dynamics. Based on the left and right representations of the Heisenberg-Weyl algebra, the algebraic structure of the master equation is explored and exact analytical solutions of this system are obtained. It is shown that for such a system, the environment can produce entanglement in contrast to its commonly believed role of destroying entanglement. In addition, the collective zero-mode eigen solutions of the system are found to be free of decoherence against the dissipation of the environment. These decoherence-free states may be useful in quantum information and quantum computation.

quant-ph

Production of squeezed state of single mode cavity field by the coupling of squeezed vacuum field reservoir in nonautonomous case

The dissipative and decoherence properties as well as the asymptotic behavior of the single mode electromagnetic field interacting with the time-dependent squeezed vacuum field reservoir are investigated in detail by using the algebraic dynamical method. With the help of the left and right representations of the relevant $hw(4)$ algebra, the dynamical symmetry of the nonautonomous master equation of the system is found to be $su(1,1)$. The unique equilibrium steady solution is found to be the squeezed state and any initial state of the system is proved to approach the unique squeezed state asymptotically. Thus the squeezed vacuum field reservoir is found to play the role of a squeezing mold of the cavity field.

quant-ph

Dynamical symmetry and analytical solutions of the non-autonomous quantum master equation of the dissipative two-level system: decoherence of quantum register

Based on the non-autonomous quantum master equation, we investigate the dissipative and decoherence properties of the two-level atom system interacting with the environment of thermal quantum radiation fields. For this system, by a novel algebraic dynamic method, the dynamical symmetry of the system is found, the quantum master equation is converted into a Schrödinger-like equation and the non-Hermitian rate (quantum Liouville) operator of the master equation is expressed as a linear function of the dynamical u(2) generators. Furthermore, the integrability of the non-autonomous master equation has been proved for the first time. Based on the time-dependent analytical solutions, the asymptotic behavior of the solution has been examined and the approach to the equilibrium state has been proved. Finally, we have studied the decoherence property of the multiple two-level atom system coupled to the thermal radiation fields, which are related to the quantum register.

quant-ph

A two-level atom coupled to a controllable squeezed vacuum field reservoir

The dissipative and decoherence properties of the two-level atom interacting with the squeezed vacuum field reservoir are investigated based on the nonautonomous master equation of the atomic density matrix in the framework of algebraic dynamics. The nonautonomous master equation is converted into a Schrödinger-like equations and its dynamical symmetry is found based on the left and right representations of the relevant algebra. The time-dependent solution and the steady solution are obtained analytically. The asymptotic behavior of the solution is examined and the approach to the equilibrium state is proved. Based on the analytic solution the response of the system to the squeezed vacuum field reservoir is studied numerically.

quant-ph

Retrieving the missed particle-antiparticle degrees of freedom of Dirac particles

The missed particle-antiparticle degrees of freedom are retrieved and the corresponding particle-antiparticle intrinsic space are introduced to study the dynamical symmetry of the Dirac particle. As a result, the particle-antiparticle quantum number appears naturally and the Dirac particle has five quantum numbers instead of four. An anti-symmetry (different from the conventional symmetry) of the Dirac Hamiltonian and a dual symmetry of its eigenfunctions are explored. The $\hatκ$ operator of the Dirac equation in central potentials is found to be the analog of the helicity operator of the free particle--the alignment of the spin along the angular momentum.

hep-th

Isospin Effect on the Process of Multifragmentation and Dissipation at Intermediate Energy Heavy Ion Collisions

In the simulation of intermediate energy heavy ion collisions by using the isospin dependent quantum molecular dynamics, the isospin effect on the process of multifragmentation and dissipation has been studied. It is found that the multiplicity of intermediate mass fragments $N_{imf}$ for the neutron-poor colliding system is always larger than that for the neutron-rich system, while the quadrupole of single particle momentum distribution $Q_{zz}$ for the neutron-poor colliding system is smaller than that of the neutron-rich system for all projectile-target combinations studied at the beam energies from about 50MeV/nucleon to 150MeV/nucleon. Since $Q_{zz}$ depends strongly on isospin dependence of in-medium nucleon-nucleon cross section and weakly on symmetry potential at the above beam energies, it may serve as a good probe to extract the information on the in-medium nucleon-nucleon cross section. The correlation between the multiplicity $N_{imf}$ of intermediate mass fragments and the total numer of charged particles $N_c$ has the behavior similar to $Q_{zz}$, which can be used as a complementary probe to the in-medium nucleon-nucleon cross section.

nucl-th

Entrance channel dependence and isospin dependence of preequilibrium nucleon emission in intermediate energy heavy ion collisions

Using isospin dependent quantum molecular dynamical model, the studies of the isospin effect on preequilibrium nucleon emission in heavy ion collisions under different entrance channel conditions show that the ratio of preequilibrium neutron number to proton number depends strongly on symmetry potential, beam energy, and the ratio of neutron to proton of the colliding system, but weakly on isospin dependent in-medium nucleon-nucleon cross sections, impact parameter, Pauli potential, and momentum dependent interaction in the energy region from 45MeV/u up to 150 MeV/u where the dynamics is dominated by nucleon-nucleon collisions. In addition, the ratio of preequilibrium neutron number to proton number for a neutron-rich colliding system is larger than the initial value of the ratio of the colliding system, but the ratio for a neutron-deficient system is less than the initial value.

nucl-th

Nuclear Stopping as A Probe to In-medium Nucleon-nucleon Cross Section in Intermediate Energy Heavy Ion Collisions

Using an isospin-dependent quantum molecular dynamics, nuclear stopping in intermediate heavy ion collisions has been studied. The calculation has been done for colliding systems with different neutron-proton ratios in beam energy ranging from 15MeV/u to 150MeV/u. It is found that, in the energy region from above Fermi energy to 150MeV/u, nuclear stopping is very sensitive to the isospin dependence of in-medium nucleon-nucleon cross section, but insensitive to symmetry potential. From this investigation, we propose that nuclear stopping can be used as a new probe to extract the information on the isospin dependence of in-medium nucleon-nucleon cross section in intermediate energy heavy ion collisions.

nucl-th

Distilling a Greenberger-Horne-Zeilinger State From an Arbitrary Pure State of Three Qubits

We present a general algorithm to achieve local operators which can produce the GHZ state for an arbitrary given three-qubit state. Thus the distillation process of the state can be realized optimally. The algorithm is shown to be sufficient for the three-qubit state on account of the fact that any state for which this distillation algorithm is invalid cannot be distilled to the GHZ state by any local actions. Moreover, an analytical result of distillation operations is achieved for the general state of three qubits.

quant-ph

Damping of Collective Nuclear Motion and Thermodynamic Properties of Nuclei beyond Mean Field

The dynamical description of correlated nuclear motion is based on a set of coupled equations of motion for the one-body density matrix $ρ(11';t)$ and the two-body correlation function $c_2(12,1'2';t)$, which is obtained from the density-matrix hierarchy beyond conventional mean-field approaches by truncating 3-body correlations. The resulting equations nonperturbatively describe particle-particle collisions (short-range correlations) as well as particle-hole interactions (long-range correlations). Within a basis of time-dependent Hartree-Fock states these equations of motion are solved for collective vibrations of $^{40}Ca$ at several finite thermal excitation energies corresponding to temperatures $T=0-6$ MeV. Transport coefficients for friction and diffusion are extracted from the explicit solutions in comparison to the solutions of the associated TDHF, VUU, Vlasov or damped quantum oscillator equations of motion. We find that the actual magnitude of the transport coefficients is strongly influenced by partlicle-hole correlations at low temperature which generate large fluctuations in the nuclear shape degrees of freedom. Thermodynamically, the specific heat and the entropy of the system as a function of temperature does not differ much from the mean-field limit except for a bump in the specific heat around $T\simeq 4$ MeV which we attribute to the melting of shell effects in the correlated system.

nucl-th

Equation of motion approach to the solution of Anderson model

Based on an equation of motion approach the single impurity Anderson model(SIAM) is reexamined. Using the cluster expansions the equations of motion of Green functions are transformed into the corresponding equations of motion of connected Green functions, which provides a natural and uniform truncation scheme. A factor of two missing in the Lacroix's approximation for the Kondo temperature is gained in the next higher order truncation beyond Lacroix's. A quantitative improvement in the density of states at the Fermi level is also obtained.

cond-mat.str-el

Correlation Dynamics of Green's Functions

We generalize the methods used in the theory of correlation dynamics and establish a set of equations of motion for many-body correlation green's functions in the non-relativistic case. These non-linear and coupled equations of motion describe the dynamical evolution of correlation green's functions of different order and transparently show how many-body correlations are generated by the different interaction terms in a genuine nonperturbative framework. The nonperturbative results of the conventional green's function theory are included in the present formalism as two limiting cases (the so-called ladder diagram summation and ring diagram summation) as well as the familiar correlation dynamics of density-matrices in the equal time limit. We present explicit expressions for three- and four-body correlation functions that can be used to dynamically restore the trace relations for spin-symmetric fermi systems and study numerically the relative importance of two-, three- and four-body correlations for nuclear configurations close to the groundstate.

nucl-th