Review of Feynman’s Path Integral in Quantum Statistics:from the Molecular Schrödinger Equation to Kleinert’s Variational Perturbation Theory

Feynman’s path integral reformulates the quantum Schrödinger differential equation to be an integral equation.It has been being widely used to compute internuclear quantum-statistical effects on many-body molecular systems.In this Review,the molecular Schrödinger equation will first be introduced,together with the BornOppenheimer approximation that decouples electronic and internuclear motions.Some effective semiclassical potentials,e.g.,centroid potential,which are all formulated in terms of Feynman’s path integral,will be discussed and compared.These semiclassical potentials can be used to directly calculate the quantum canonical partition function without individual Schrödinger’s energy eigenvalues.As a result,path integrations are conventionally performed with Monte Carlo and molecular dynamics sampling techniques.To complement these techniques,we will examine how Kleinert’s variational perturbation(KP)theory can provide a complete theoretical foundation for developing non-sampling/non-stochastic methods to systematically calculate centroid potential.To enable the powerful KP theory to be practical for many-body molecular systems,we have proposed a new path-integral method:automated integrationfree path-integral(AIF-PI)method.Due to the integration-free and computationally inexpensive characteristics of our AIF-PI method,we have used it to perform ab initio path-integral calculations of kinetic isotope effects on proton-transfer and RNA-related phosphoryl-transfer chemical reactions.The computational procedure of using our AIF-PI method,along with the features of our new centroid path-integral theory at the minimum of the absolute-zero energy(AMAZE),are also highlighted in this review.

Variational quantum simulation of thermal statistical states on a superconducting quantum processer

Quantum computers promise to solve finite-temperature properties of quantum many-body systems,which is generally challenging for classical computers due to high computational complexities.Here,we report experimental preparations of Gibbs states and excited states of Heisenberg X X and X X Z models by using a 5-qubit programmable superconducting processor.In the experiments,we apply a hybrid quantum–classical algorithm to generate finite temperature states with classical probability models and variational quantum circuits.We reveal that the Hamiltonians can be fully diagonalized with optimized quantum circuits,which enable us to prepare excited states at arbitrary energy density.We demonstrate that the approach has a self-verifying feature and can estimate fundamental thermal observables with a small statistical error.Based on numerical results,we further show that the time complexity of our approach scales polynomially in the number of qubits,revealing its potential in solving large-scale problems.

Level Statistics Crossover of Chiral Surface States in a Three-Dimensional Quantum Hall System

Recent experiments have demonstrated the realization of the three-dimensional quantum Hall effect in highly anisotropic crystalline materials, such as ZrTe|_5 and BaMnSb_2. Such a system supports chiral surface states in the presence of a strong magnetic field, which exhibit a one-dimensional metal-insulator crossover due to suppression of surface diffusion by disorder potential. We study the nontrivial surface states in a lattice model and find a wide crossover of the level-spacing distribution through a semi-Poisson distribution. We also discover a nonmonotonic evolution of the level statistics due to the disorder-induced mixture of surface and bulk states.

Quantum Statistical Entropy of Five-Dimensional Black Hole

The generalized uncertainty relation is introduced to calculate quantum statistic entropy of a black hole. By using the new equation of state density motivated by the generalized uncertainty relation, we discuss entropies of Bose field and Fermi field on the background of the five-dimensional spacetime. In our calculation, we need not introduce cutoff. There is not the divergent logarithmic term as in the original brick-wall method. And it is obtained that the quantum statistic entropy corresponding to black hole horizon is proportional to the area of the horizon. Fhrther it is shown that the entropy of black hole is the entropy of quantum state on the surface of horizon. The black hole＇s entropy is the intrinsic property of the black hole. The entropy is a quantum effect. It makes people further understand the quantum statistic entropy.

Quantum Properties of Two-Mode Squeezed Even and Odd Coherent States

Two new types of quantum states are constructed by applying the operator s（ξ） = exp（ξ＊ ab - ξa＋b＋） on the two-mode even and odd coherent states. The mathematical and quantum statistical properties of such states are investigated. Various nonclassical features of these states, such as squeezing properties, the inter-mode photon bunching, and the violation of Cauchy-Schwarz inequality, are discussed. The Wigner function in these states are studied in detail.

Temperature and hydrogen-like impurity effects on the excited state of the strong coupling bound polaron in a CsI quantum pseudodot

With hydrogen-like impurity（HLI） located in the center of Cs I quantum pseudodot（QPD） and by using the variational method of Pekar type（VMPT）, we investigate the first-excited state energy（FESE）, excitation energy and transition frequency of the strongly-coupled bound polaron in the present paper. Temperature effects on bound polaron properties are calculated by employing the quantum statistical theory（QST）. According to the present work＇s numerical results, the FESE, excitation energy and transition frequency decay（amplify） with raising temperature in the regime of lower（higher）temperature. They are decreasing functions of Coulomb impurity potential strength.

Total Quantum Statistical Entropy of Reissner-Nordstrom Black Holes： in Dirac Field Case

The total quantum statistical entropy of Reissner-Nordstrom black holes inDirac field case is evaluated in this article. The space-time of the black holes is divided intothree regions: region 1 (r 】 r_o), region 2 (r_o 】 r 】 r_i), and region 3 (r_i 】 r 】 0), where r_ois the radius of the outer event horizon, and Ti is the radius of the inner event horizon. The totalquantum statistical entropy of Reissner-Nordstrom black holes is S = S_1 + S_2 + S_3, where S_i (i= 1,2,3) is the entropy, contributed by regions 1,2,3. The detailed calculation shows that S_2 isneglectfully small. S_1 = w_t(π~2/45)k_b(A_o/ε~2β~3), S_3 = -w_t(π~2/45)k_b(A_i/ε~2β~3), whereA_o and A_i are, respectively, the areas of the outer and inner event horizons, w_t = 2~s[1 -2~(-(s+1))], s = d/2, d is the space-time dimension, here d = 4, s = 2. As r_i approaches r_o in theextreme case the total quantum statistical entropy of Reissner-Nordstrom black holes approacheszero.

Statistical Behaviors of Quantum Spectra in Superheavy Nuclei

From the point of view of the interplay between order and chaos, the most regular single-particle motion of neutrons has been found in the superheavy system with and based on the Skyrme–Hartree–Fock model and in the system with and based on the relativistic mean-field model. It has been shown that the statistical analysis of spectra can give valuable information about the stability of suprheavy systems. In addition it may yield deep insight into the single-particle motion in the mean field formed by the superheavy system.

Statistical Mechanics for Weak Measurements and Quantum Inseparability

In weak measurement thought experiment, an ensemble consists of M quantum particles and N states. We observe that separability of the particles is lost, and hence we have fuzzy occupation numbers for the particles in the ensemble. Without sharply measuring each particle state, quantum interferences add extra possible configurations of the ensemble, this explains the Quantum Pigeonhole Principle. This principle adds more entropy to the system;hence the particles seem to have a new kind of correlations emergent from particles not having a single, well-defined state. We formulated the Quantum Pigeonhole Principle in the language of abstract Hilbert spaces, then generalized it to systems consisting of mixed states. This insight into the fundamentals of quantum statistical mechanics could help us understand the interpretation of quantum mechanics more deeply, and possibly have implication on quantum computing and information theory.

Long-range interacting Stark many-body probes with super-Heisenberg precision

In contrast to interferometry-based quantum sensing,where interparticle interaction is detrimental,quantum many-body probes exploit such interactions to achieve quantum-enhanced sensitivity.In most of the studied quantum many-body probes,the interaction is considered to be short-ranged.Here,we investigate the impact of long-range interaction at various filling factors on the performance of Stark quantum probes for measuring a small gradient field.These probes harness the ground state Stark localization phase transition which happens at an infinitesimal gradient field as the system size increases.Our results show that while super-Heisenberg precision is always achievable in all ranges of interaction,the long-range interacting Stark probe reveals two distinct behaviors.First,by algebraically increasing the range of interaction,the localization power is enhanced and thus the sensitivity of the probe decreases.Second,as the interaction range becomes close to a fully connected graph its effective localization power disappears and thus the sensitivity of the probe starts to enhance again.The super-Heisenberg precision is achievable throughout the extended phase until the transition point and remains valid even when the state preparation time is incorporated in the resource analysis.As the probe enters the localized phase,the sensitivity decreases and its performance becomes size-independent,following a universal behavior.In addition,our analysis shows that lower filling factors lead to better precision for measuring weak gradient fields.

Entropy of a rotating and charged black string to all orders in the Planck length

By using the entanglement entropy method, this paper calculates the statistical entropy of the Bose and Fermi fields in thin films, and derives the Bekenstein-Hawking entropy and its correction term on the background of a rotating and charged black string. Here, the quantum field is entangled with quantum states in the black string and thin film to the event horizon from outside the rotating and charged black string. Taking into account the effect of the generalized uncertainty principle on quantum state density, it removes the difficulty of the divergence of state density near the event horizon in the brick-wall model. These calculations and discussions imply that high density quantum states near the event horizon of a black string are strongly correlated with the quantum states in a black string and that black string entropy is a quantum effect. The ultraviolet cut-off in the brick-wall model is not reasonable. The generalized uncertainty principle should be considered in the high energy quantum field near the event horizon. From the viewpoint of quantum statistical mechanics, the correction value of Bekenstein-Hawking entropy is obtained. This allows the fundamental recognition of the correction value of black string entropy at nonspherical coordinates.

Gedanken Experiment for Degree of Flatness, or Lack of, in Early Universe Conditions

This document will from first principles delineate the degree of flatness, or deviations from, in early universe models. We will, afterwards, make comparison with recent results we have looked at concerning metric tensor fluctuations and comment upon the role of what early universe gravitational energy may play a role in the presumed deviation from flat space results. Note that N~Sinitial(graviton)~1037 will be tied into the presumed results for initial state density, in ways we will comment upon, leading to observations which are supporting the physics given by Equation (26) of this document as with regards to Gravitational waves, from relic conditions. The deviations from flat space may help confirm the conclusions given by Buchert, Carfora, Kolb, and Wiltshire allegedly refuting the claim by Green and Wald that “the standard FLRW model approximates our Universe extremely well on all scales, except close to strong field astrophysical objects”, as well as give additional analysis appropriate for adding detail to expanding experimental procedures for investigating non FLRW models such as the Polynomial Inflation models as given by Kobayashi, and Seto, as well as other nonstandard cosmologies, as brought up by Corda, and other researchers. As well as improve upon post Bicep 2 measurements which will avoid GW signatures from interstellar dust, as opposed to relic GW. We hope that our approach may help in the differentiation between different cosmology models. Most importantly, our procedure may help, with refinement of admissible frequency range, avoid the problem of BICEP 2, which had its presumed GW signals from presumed relic conditions identical to dust induced frequencies, as so identified by the Planck collaboration in reference [25] which we comment upon in the conclusion.

Enhanced electron positron pair creation by the frequency chirped laser pulse

Based on the quantum Vlasov equation, the effect of frequency chirp on electron-positron pair production is investigated. The cycle parameter, which characterizes the laser field cycle degree within the pulse, is also considered. In both supercycle and subcycle laser pulses the frequency chirp can greatly enhance the momentum distribution function of created pairs and the pair number density. The pair number density created by a supercycle laser pulse is larger than that by a subcycle pulse under the same laser frequency and chirping. There exists an optimal cycle parameter corresponding to the maximum value of the created pair number density for different chirp rates. It is found that the pair number density is sensitive/insensitive to chirping rate when the cycle parameter lies below/above the optimal one.

Bekenstein-Hawking Cosmological Entropy and Correction Term Corresponding Cosmological Horizon of Rotating and Charged Black String

Utilizing the quantum statistical method and applying the new state density equation motivated by generalized uncertainty principle in quantum gravitaty, we avoid the difficulty in solving wave equation and directly calculate the partition function of bosonic and fermionic field on the background of rotating and charged black string. Then near the cosmological horizon, entropies of bosonic and fermionic field are calculated on the background of black string. When constant A introduced in generalized uncertainty principle takes a proper value, we derive Bekenstein- Hawking entropy and the correction value corresponding cosmologicaJ horizon on the background of rotating and charged black string. Because we use the new state density equation, in our calculation there are not divergent term and small mass approximation in the original brick-wall method. From the view of quantum statistic mechanics, the correction value to Bekenstein-Hawking entropy of the black string is derived. It makes people deeply understand the correction value to the entropy of the black string cosmological horizon in non-spherical coordinate spacetime.

Gedanken Experiment for Using Boltzmann Equation for Relic Graviton Frequencies, in Pre-Planckian Physics and the Independence of Relic Graviton Density from Either Single Repeating Universe Models or Multiverses

We look at what may occur if Boltzmann equations, as presented by Murayama in 2007, Les Houches, are applied to graviton density in a pre-Planckian universe setting. Two restrictions are in order. First of all, we are assuming a graviton mass on the order of 10?62 grams, as if the pre-Planckian regime does not change the nature of Graviton mass, in its low end. Secondly, we are also assuming that a comparatively low temperature regime (far below the Planckian temperature) exists. Finally we are leaving unsaid what may happen if Gravitational waves enter the Planck regime of ultra-high temperature. With those three considerations, we proceed to examine a Graviton density value resulting from perturbation from low to higher temperatures. In the end an ultra- hot Pre big bang cosmology will yield essentially no early universe information transfer crossovers to our present cosmological system. This is not affected by the choice if we have a single repeating universe, or a multiverse. A cold pre inflationary state yields a very different situation. Initial frequencies of Gravitons, though, as outlined may be different in the multiverse case, as opposed to the single repeating universe case. We close with comments as to Bicep 2, and how this document has material as to how to avoid the BICEP 2 disaster. And about choosing between either the possibility of massless Scalar-Tensor Gravity as the correct theory of gravitation or conventional GR.

Non-Linear Electrodynamics Gedanken Experiment for Modified Zero Point Energy and Planck’s “Constant”, h Bar, in the Beginning of Cosmological Expansion, So h(Today) = h(Initial). Also How to Link Gravity, Quantum Mechanics, and E and M through Initial Entropy Production in the Early Universe

We initially look at a nonsingular universe representation of entropy, based in part on what is brought up by Muller and Lousto. This is a gateway to bring up information and computational steps (as defined by Seth Lloyd) as to what will be available initially due to a modified Zero Point Energy formalism. The Zero Point Energy formalism is modified as due to Vissers’s setting of an angular plane number in early universe cosmology as k(maximum) ~ 1/(Planck length), with a specific initial density giving rise to initial information content which may permit fixing the initial Planck’s constant, h, which is pivotal to the setting of physical law. This will be in the spirit of Stoica’s removal of initial conditions of non-pathological initial starting points in Cosmology. What we want are necessary and sufficient conditions so h(today) = h(initial). We also in addition make a brief survey into 5th force arguments in gravity which also has a strict entropy interpretation. i.e., how to link gravity, quantum mechanics, and E and M through entropy production.

Evolution of a Thermo Vacuum State in a Single-Mode Amplitude Dissipative Channel

We investigate how an initial thermo vacuum state, in the context of thermo field dynamics, evolves in a single-mode amplitude dissipative channel, and find that in this process the thermo squeezing effect decreases while the fictitious-mode vacuum becomes chaotic.

The components transitive regularity of three dosage forms of Liuwei Dihuang Fufang

Objective To explore the transitive regularity of holistic constituents from the crude slices of the medicinal raw materials(MCS)to the formula granules(FG),fufang decoction(FD),and finally,the concentrated pills(CP)of Liuwei Dihuang Fufang(六味地黄复方,LWDHF).Methods Samples for MCS,FG,FD,and CP of LWDHF were obtained,and a fingerprint data-base was established using high-performance liquid chromatography(HPLC),by separating the samples in an XB-C18 column and analyzing the transitive regularity of components us-ing the total quantum statistical moment(TQSM),including total quantum zero moment(AUCT),total quantum first moment(MRTT),total quantum second moment(VRTT),and its similarity approach.The AUCT,MRTT,and VRTT were calculated based on the representative HPLC chromatograms of FG,FD,and CP of LWDHF.Results AUCT of FG,FD,and CP of LWDHF was 71804,46553,and 144646μV·s,respectively;MRTT was 14.43,14.54,and 18.85 min,respectively;and VRTT was 106.98,112.84,and 269.12 min2,respectively.Comparing the similarity of FG/FD,FG/CP and FD/CP of LWDHF,the TQSM similarity values were 98.66%,76.62%,and 75.37%,respectively,whereas the tradi-tional similarity evaluation values were 98.68%,85.43%,and 85.60%,respectively.Conclusion The results perform little distinction in the total composition between FG and FD,whereas some distinction existed between FD and CP.Experimental evidence,therefore indicates that FG could be used as the alternative of MCS in clinical applications.

On Husimi Distribution for Systems with Continuous Spectrum

We propose a procedure to generalize the Husimi distribution to systems with continuous spectrum. We start examining a pioneering work, by Gazeau and Klauder, where the concept of coherent states for systems with discrete spectrum was extended to systems with continuous one. In the present article, we see the Husimi distribution as a representation of the density operator in terms of a basis of coherent states. There are other ways to obtain it, but we do not consider here. We specially discuss the problem of the continuous harmonic oscillator.

Thermal properties of Lense-Thirring spacetime in tetrad theory of gravity

Using the divergence term appearing in the Lagrangian of the teleparallel equivalent of general relativity （TEGR）, we calculate the thermodynamic quantities of four tetrads＇ spacetime reproducing Lense-Thirring （LT） metric. We also investigate the first law of thermodynamics and the quantum statistical relation.