Proton enhancement at large pT at the CERN large hadron collider without structure in associated-particle distribution

The production of pions and protons in the pT range between 10 and 20 GeV/c for Pb+Pb collisions at CERN LHC is studied in the recombination model. It is shown that the dominant mechanism for hadronization is the recombination of shower partons from neighboring jets when the jet density is high. Protons are more copiously produced than pions in that pT range because the coalescing partons can have lower momentum fractions, but no thermal partons are involved. The proton-to-pion ratio can be as high as 20. When such high pT hadrons are used as trigger particles, there will not be any associated particles that are not in the background.     

Diffraction tomography without phase information

A modified form of diffraction tomography is presented in which measurements of the phase of the scattered field are replaced with measurements of the intensity on two planes beyond the scatterer. The new method is illustrated by an example.     

Effective information loss outside the horizon

If a system falls through a black hole horizon, then its information is lost to an observer at infinity. But we argue that the accessible information is lost before the horizon is crossed. The temperature of the hole limits information carrying signals from a system that has fallen too close to the horizon. Extremal holes have T = 0, but there is a minimum energy required to emit a quantum in the short proper time left before the horizon is crossed. If we attempt to bring the system back to infinity for observation, then acceleration radiation destroys the information. All three considerations give a critical distance from the horizon \({d\sim \sqrt\frac{r_H}{\Delta E}}\), where r _H is the horizon radius and ΔE is the energy scale characterizing the system. For systems in string theory where we pack information as densely as possible, this acceleration constraint is found to have a geometric interpretation. These estimates suggest that in theories of gravity we should measure information not as a quantity contained inside a given system, but in terms of how much of that information can be reliably accessed by another observer.     

Quantum information is incompressible without errors

A classical random variable can be faithfully compressed into a sequence of bits with its expected length lying within one bit of Shannon entropy. We generalize this variable-length and faithful scenario to the general quantum source producing mixed states rho(i) with probability p(i). In contrast to the classical case, the optimal compression rate in the limit of large block length differs from the one in the fixed-length and asymptotically faithful scenario. The amount of this gap is interpreted as the genuinely quantum part being incompressible in the former scenario.     

Particle occupation factors without large number approximations

New derivations of particle occupation factors that are based on mean values and do not require large number approximations (LNA) are provided for fermions, bosons, and Boltzmann particles. The derivations are closely related to traditional combinatorial approaches, so the physical content of the latter is preserved without recourse to most probable values or LNA. The approach is based on the use of eigenvalues of the density matrix as probabilities entering into the Shannon entropy. The degeneracies of the eigenvalues of the density matrix can be identified with Boltzmann enumeration factors. Problems associated with steepest descent procedures, limit theorem techniques, and the Boltzmann thermodynamic probability are avoided. In addition, since the approach is based on the eigenvalues of the density matrix, the concept of ensembles is not required.     

Remote atomic information concentration without Bell-state measurement

This paper proposes a scheme for information concentration of two remote two-level atoms in cavity QED. This scheme does not involve the Bell-state measurement. During the interaction between atom and cavity, the cavity frequency is large-detuned from the atomic transition frequency, thus the scheme is insensitive to both the cavity decay and the thermal field. This idea can directly be generalized in the case of multi-atom information concentration.     

Two quantum dialogue protocols without information leakage

By swapping the entanglement of Bell states, we propose two quantum dialogue protocols, which have two different characters, one with the “two-step” character and the other with the “ping-pong” character. The common merits of two dialogue protocols are that the information leakage does not exist.     

Universality at large N

We prove that corresponding O(N), U(N), and Sp(N) lattice gauge theories give the same Wilson loops as N → ∞. Therefore, magnetic monopoles cannot be significant in this limit.     

Coherence loss of large fields interacting with two-level atoms

Preliminary results are reported on the coherence properties of a large and initially coherent e.m. field interacting with a set of resonant two-level atoms. The field is shown to behave non-classically relatively large times, since its variance increases linearly with time.     

基于大数据信息的软件测试方法改进研究

传统软件测试方法中,由于各种实验参数设置没有准确依据数学理论,涉及到的软件测试算法都存在效率偏低的问题。为此,提出基于大数据信息改进的软件测试方法,首先在大数据的背景下,对测试软件目的展开分析,将人的智慧与机器相互结合,通过对社会群体认知与数据价值提炼,使数据从机器智能分析到人类与机器智慧结合的转变。然后对大数据信息软件的三种测试方法进行探讨,第一种是利用粒子群为主线的优化算法,引入蚁群算法作为大数据信息处理机制,可以有效处理大数据信息;第二种就是针对软件特点,提出基于大数据信息处理模型的软件测试方法,通过模型对输入数据进行计算并得出结果;第三种采用仿真原理对软件进行测试。实验结果证明,基于大数据信息软件改进的测试方法不仅可以有效处理数据,还可以提高数据测试效率和软件定位,为今后的软件测试提供有力依据。