565 research outputs found
Necessity of integral formalism
To describe the physical reality, there are two ways of constructing the
dynamical equation of field, differential formalism and integral formalism. The
importance of this fact is firstly emphasized by Yang in case of gauge field
[Phys. Rev. Lett. 33 (1974) 445], where the fact has given rise to a deeper
understanding for Aharonov-Bohm phase and magnetic monopole [Phys. Rev. D. 12
(1975) 3845]. In this paper we shall point out that such a fact also holds in
general wave function of matter, it may give rise to a deeper understanding for
Berry phase. Most importantly, we shall prove a point that, for general wave
function of matter, in the adiabatic limit, there is an intrinsic difference
between its integral formalism and differential formalism. It is neglect of
this difference that leads to an inconsistency of quantum adiabatic theorem
pointed out by Marzlin and Sanders [Phys. Rev. Lett. 93 (2004) 160408]. It has
been widely accepted that there is no physical difference of using differential
operator or integral operator to construct the dynamical equation of field.
Nevertheless, our study shows that the Schrodinger differential equation (i.e.,
differential formalism for wave function) shall lead to vanishing Berry phase
and that the Schrodinger integral equation (i.e., integral formalism for wave
function), in the adiabatic limit, can satisfactorily give the Berry phase.
Therefore, we reach a conclusion: There are two ways of describing physical
reality, differential formalism and integral formalism; but the integral
formalism is a unique way of complete description.Comment: 13Page; Schrodinger differential equation shall lead to vanishing
Berry phas
Asymmetry of parallel flow on the Large Helical Device
An asymmetric parallel return flow, which modifies the parallel component of the flow, is expected to meet the zero divergence of the flow on a flux surface based on the common neoclassical theory for torus plasma. The full flow structure is measured by charge exchange spectroscopy on the Large Helical Device. Inboard/outboard asymmetry of the parallel flow is observed according to the full flow profile measurement. Flow asymmetry is considered to be induced by the Pfirsch–Schlüter flow closely associated with the radial electric field. A linear relationship between the integrated flow asymmetry and the electric potential difference is obtained in different magnetic fields and configurations. A model based upon the incompressibility of the flow is applied to acquire a geometric factor hB, which only connects to the magnetic configuration from the experiment. The asymmetric component of the parallel flow measured is compared with the asymmetric component of parallel flow calculated in the incompressibility conditions of flow on the magnetic flux surface. The measured asymmetric flow is consistent with the calculation in plasma with a small toroidal torque input in the inward shifted configuration. However, the measured asymmetric flow is significantly smaller than that calculated for plasma with a large toroidal torque or in the outward shifted configuration. One possible explanation for this variation could be radial transport due to anomalous perpendicular viscosity as well as strongly poloidally asymmetric radial flow
Energy Spectrum of Bloch Electrons Under Checkerboard Field Modulations
Two-dimensional Bloch electrons in a uniform magnetic field exhibit complex
energy spectrum. When static electric and magnetic modulations with a
checkerboard pattern are superimposed on the uniform magnetic field, more
structures and symmetries of the spectra are found, due to the additional
adjustable parameters from the modulations. We give a comprehensive report on
these new symmetries. We have also found an electric-modulation induced energy
gap, whose magnitude is independent of the strength of either the uniform or
the modulated magnetic field. This study is applicable to experimentally
accessible systems and is related to the investigations on frustrated
antiferromagnetism.Comment: 8 pages, 6 figures (reduced in sizes), submitted to Phys. Rev.
Measurement of branching fractions for the inclusive Cabibbo-favored ~K*0(892) and Cabibbo-suppressed K*0(892) decays of neutral and charged D mesons
The branching fractions for the inclusive Cabibbo-favored ~K*0 and
Cabibbo-suppressed K*0 decays of D mesons are measured based on a data sample
of 33 pb-1 collected at and around the center-of-mass energy of 3.773 GeV with
the BES-II detector at the BEPC collider. The branching fractions for the
decays D+(0) -> ~K*0(892)X and D0 -> K*0(892)X are determined to be BF(D0 ->
\~K*0X) = (8.7 +/- 4.0 +/- 1.2)%, BF(D+ -> ~K*0X) = (23.2 +/- 4.5 +/- 3.0)% and
BF(D0 -> K*0X) = (2.8 +/- 1.2 +/- 0.4)%. An upper limit on the branching
fraction at 90% C.L. for the decay D+ -> K*0(892)X is set to be BF(D+ -> K*0X)
< 6.6%
Direct Measurements of the Branching Fractions for and and Determinations of the Form Factors and
The absolute branching fractions for the decays and
are determined using singly
tagged sample from the data collected around 3.773 GeV with the
BES-II detector at the BEPC. In the system recoiling against the singly tagged
meson, events for and events for decays are observed. Those yield
the absolute branching fractions to be and . The
vector form factors are determined to be
and . The ratio of the two form
factors is measured to be .Comment: 6 pages, 5 figure
Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta
Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector,
the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are
measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and
(7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure
BESII Detector Simulation
A Monte Carlo program based on Geant3 has been developed for BESII detector
simulation. The organization of the program is outlined, and the digitization
procedure for simulating the response of various sub-detectors is described.
Comparisons with data show that the performance of the program is generally
satisfactory.Comment: 17 pages, 14 figures, uses elsart.cls, to be submitted to NIM
A Measurement of Psi(2S) Resonance Parameters
Cross sections for e+e- to hadons, pi+pi- J/Psi, and mu+mu- have been
measured in the vicinity of the Psi(2S) resonance using the BESII detector
operated at the BEPC. The Psi(2S) total width; partial widths to hadrons,
pi+pi- J/Psi, muons; and corresponding branching fractions have been determined
to be Gamma(total)= (264+-27) keV; Gamma(hadron)= (258+-26) keV, Gamma(mu)=
(2.44+-0.21) keV, and Gamma(pi+pi- J/Psi)= (85+-8.7) keV; and Br(hadron)=
(97.79+-0.15)%, Br(pi+pi- J/Psi)= (32+-1.4)%, Br(mu)= (0.93+-0.08)%,
respectively.Comment: 8 pages, 6 figure
The pole in
Using a sample of 58 million events recorded in the BESII detector,
the decay is studied. There are conspicuous
and signals. At low mass, a large
broad peak due to the is observed, and its pole position is determined
to be - MeV from the mean of six analyses.
The errors are dominated by the systematic errors.Comment: 15 pages, 6 figures, submitted to PL
Study of
New data are presented on from a sample of 58M
events in the upgraded BES II detector at the BEPC. There is a
conspicuous signal for and a peak at higher mass which
may be fitted with . From a combined analysis with
data, the branching ratio
is at the 95%
confidence level.Comment: 11 pages, 5 figures. Submitted to Phys. Lett.
- …