10,482 research outputs found
Variational Perturbation Theory for Markov Processes
We develop a convergent variational perturbation theory for conditional
probability densities of Markov processes. The power of the theory is
illustrated by applying it to the diffusion of a particle in an anharmonic
potential.Comment: Author Information under
http://www.physik.fu-berlin.de/~kleinert/institution.html Latest update of
paper also at http://www.physik.fu-berlin.de/~kleinert/33
Strong-Coupling Calculation of Fluctuation Pressure of a Membrane Between Walls
We calculate analytically the proportionality constant in the pressure law of
a membrane between parallel walls from the strong-coupling limit of variational
perturbation theory up to third order. Extrapolating the zeroth to third
approximations to infinity yields the pressure constant alpha=0.0797149. This
result lies well within the error bounds of the most accurate available
Monte-Carlo result 0.0798 +- 0.0003.Comment: Author Information under
http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of
paper also at http://www.physik.fu-berlin.de/~kleinert/28
Generating Functionals for Harmonic Expectation Values of Paths with Fixed End Points. Feynman Diagrams for Nonpolynomial Interactions
We introduce a general class of generating functionals for the calculation of
quantum-mechanical expectation values of arbitrary functionals of fluctuating
paths with fixed end points in configuration or momentum space. The generating
functionals are calculated explicitly for harmonic oscillators with
time-dependent frequency, and used to derive a smearing formulas for
correlation functions of polynomial and nonpolynomials functions of
time-dependent positions and momenta. These formulas summarize the effect of
thermal and quantum fluctuations, and serve to derive generalized Wick rules
and Feynman diagrams for perturbation expansions of nonpolynomial interactions.Comment: Author Information under
http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of
paper also at http://www.physik.fu-berlin.de/~kleinert/28
Regulatory and adaptive responses of Lactococcus lactis in situ
cum laude graduation (with distinction
Quantum Monte Carlo Method for Attractive Coulomb Potentials
Starting from an exact lower bound on the imaginary-time propagator, we
present a Path-Integral Quantum Monte Carlo method that can handle singular
attractive potentials. We illustrate the basic ideas of this Quantum Monte
Carlo algorithm by simulating the ground state of hydrogen and helium.Comment: 7 pages, 3 table
IONIZED CALCIUM IN ACIDOSIS: DIFFERENTIAL EFFECT OF HYPERCAPNIC AND LACTIC ACIDOSIS
The effects of various forms of acidosis on ionized calcium concentrations were investigated in vivo in rabbits and in vitro in human plasma. Calculation of least square regression equations of ionized calcium (mM) on pH yielded the following regression coefficients in human plasma: hypercapnic acidosis —0.53±0.07; hydrochloric acidosis —0.65±0.06; lactic acidosis —0.27±0.05. These findings in human plasma are roughly paralleled by those in rabbits. From stability constants it was calculated that the formation of Ca-lactate complexes accounts for the difference between lactic and hydrochloric acidosis. It is concluded that differences in the behaviour of ionized calcium between hypercapnic and lactic acidosis might contribute to the known differences in cardiovascular effect
A dimension conjecture for q-analogues of multiple zeta values
We study a class of q-analogues of multiple zeta values given by certain formal q-series with rational coefficients. After introducing a notion of weight and depth for these q-analogues of multiple zeta values we present dimension conjectures for the spaces of their weight- and depth-graded parts, which have a similar shape as the conjectures of Zagier and Broadhurst-Kreimer for multiple zeta values
Generalized Jacobi-Trudi determinants and evaluations of Schur multiple zeta values
We present new determinant expressions for regularized Schur multiple zeta values. These generalize the known Jacobi–Trudi formulas and can be used to quickly evaluate certain types of Schur multiple zeta values. Using these formulas we prove that every Schur multiple zeta value with alternating entries in 1 and 3 can be written as a polynomial in Riemann zeta values. Furthermore, we give conditions on the shape, which determine when such Schur multiple zetas are polynomials purely in odd or in even Riemann zeta values
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