Noncommutative Inspired Reissner-Nordstrom Black Holes in Large Extra Dimensions

Recently, a new noncommutative geometry inspired solution of the coupled Einstein Maxwell field equations including black holes in 4-dimension is found. In this paper, we generalize some aspects of this model to the Reissner Nordstrom （RN） like geometries with large extra dimensions. We discuss Hawking radiation process based on noncommutative inspired solutions. In this framework, existence of black hole remnant and possibility of its detection in LHC are investigated.     

Brane Formation and Cosmological Constraint on the Number of Extra Dimensions

Special relativity is generalized to extra dimensions and quantized energy levels of particles are obtained. By calculating the probability of particles' motion in extra dimensions at high temperature of the early universe, it is proposed that the branes may have not existed since the very beginning of the universe, but formed later. Meanwhile, before the formation, particles of the universe may have filled in the whole bulk, not just on the branes. This scenario differs from that in the standard big bang cosmology in which all particles are assumed to be in the 4D spacetime. So, in brane models, whether our universe began from a 4D big bang singularity is questionable. A cosmological constraint on the number of extra dimensions is also given which favors N ≥ 7.     

Associated Productions of HZZ and HHZ at Linear Colliders in Large Extra Dimension Model

In this paper we investigate the effects of the large extra dimensions on the two processes e⁺e^-→ H⁰Z⁰Z⁰ and e⁺e^-→ H⁰Z⁰Z⁰ at linear colliders in both unpolarized and polarized collision modes. We find that the virtual Kaluza-Klein graviton exchange can significantly enhance the cross section from their standard model expectations for these two processes. The results show that the LED effect on the process e⁺e^-→ H⁰Z⁰Z⁰ allows the observation limits on the effective scale M_S to be probed up to 9.75 TeV and 10.1 TeV in the unpolarized and +-(λ_e⁺=1/2, λ_e^-=-1/2) polarized beam collision modes (with P_e⁺=0.6, P_e^-=0.8), respectively. For the process e⁺e^-→ H⁰Z⁰Z⁰, these limits on M_S can be probed up to 6.06 TeV and 6.38 TeV in the unpolarized and polarized collision modes separately. We find that the λ_e⁺=1/2, λ_e^-=-1/2 polarization collision mode in both process e⁺e^-→ H⁰Z⁰Z⁰ and e⁺e^-→ H⁰Z⁰Z⁰ may provide a possibility to improve the sensitivity in probing the LED effects.     

Stark-Chirped Rapid Adiabatic Passage in Presence of Dissipation for Quantum Computation

Stark-chirped rapid adiabatic passage （SCRAP） is an important technique used for coherent quantum controls. In this paper we investigate how the practically-existing dissipation of the system influences on the efficiency of the passage, and thus the fidelities of the SCRAP-based quantum gates. With flux-biased Josephson qubits as a specifical example, our results show clearly that the efficiency of the logic gates implemented by SCRAP are robust against the weak dissipation. The influence due to the non-adiabtic transitions between the adiabatic passages is comparatively significantly small. Therefore, the SCRAP-based logic gates should be feasible for the realistic physical systems with noises.     

Heisenberg Limit Phase Sensitivity in the Presence of Decoherence Channels

In the present study, time evolution of quantum Cramer–Rao bound of entangled N00N state, as phase sensitivity, is determined by the aid of quantum estimation theory in the presence decoherence channels. Also, the dynamic quantum process as decoherence approach is characterized by quantum fisher information flow and entanglement amount in order to distinguish between Markovian and Non-Markovian process. The comparison between quantum fisher information and quantum fisher information flow assists to comprehend the phase sensitivity evolution corresponding to Non-Markovian and Markovian process. Furthermore, as result of backflow of information from the environment to system, the phase sensitivity corresponding memory effect of environment are revived after complete decay and increase in the few times.     

Spin Pumping from a Quantum Dot in the Presence of Decoherence

We study the pumped spin current of an interacting quantum dot tunnel coupled to a single lead in the presence of electron spin resonance （ESR） field. The spin decoherence in the dot is included by the Bffttiker approach. Using the nonequilibrium Green＇s function technique, we show that ESR-induced spin flip can generate finite spin current with no charge transport. Both the Coulomb interaction and spin decoherence decrease the amplitude of spin current. The dependence of pumped spin current on the intensity and frequency of ESR field, and the spin decoherence is discussed.     

Brane Cosmology, Varying Speed of Light and Inflation in Models with One or More Extra Dimensions

We summarize the approach to brane cosmology known as mirage cosmology and use it to determine the Friedmann equation on a 3-brane embedded in different bulk spacetimes all with one or more extra dimensions. Usually, when there is more than one extra dimension the junction conditions, central to the usual brane world scenarios, are difficult to apply. This problem does not arise in mirage cosmology because the brane is treated as a test particle in the background spacetime. We discuss in detail the dynamics of a brane embedded in two specific 10D bulk spacetimes, namely Sch-AdS₅ × S₅ and a rotating black hole, and from the dynamics—which are now rather more complicated since the brane can move in all the extra dimensions—determine the new dark fluid terms in the brane Friedmann equation. Some of these, such as the cosmological constant term, are seen to be bulk dependent. We then show explicitly how this mirage cosmology approach matches with the familiar junction condition approach when there is just one extra dimension. The issue of a varying speed of light in mirage cosmology is addressed and we find a scenario in which c _eff always increases, tending asymptotically to c ₀ as the universe expands. Finally some comments are made regarding brane inflation and limitations of the mirage cosmology approach are also discussed.     

Randomized Oblivious Transfer for Secure Multiparty Computation in the Quantum Setting

Secure computation is a powerful cryptographic tool that encompasses the evaluation of any multivariate function with arbitrary inputs from mutually distrusting parties. The oblivious transfer primitive serves is a basic building block for the general task of secure multi-party computation. Therefore, analyzing the security in the universal composability framework becomes mandatory when dealing with multi-party computation protocols composed of oblivious transfer subroutines. Furthermore, since the required number of oblivious transfer instances scales with the size of the circuits, oblivious transfer remains as a bottleneck for large-scale multi-party computation implementations. Techniques that allow one to extend a small number of oblivious transfers into a larger one in an efficient way make use of the oblivious transfer variant called randomized oblivious transfer. In this work, we present randomized versions of two known oblivious transfer protocols, one quantum and another post-quantum with ring learning with an error assumption. We then prove their security in the quantum universal composability framework, in a common reference string model.     

量子环上粒子体系的计算

对于量子环上带电粒子体系,组成本征函数的基矢数及哈密顿矩阵元素数都极大,数值计算量庞大.本文介绍在处理此问题时按轨道总角动量分类从基矢集中选择子基矢集的方法和技巧.应用计算机进行数值计算时,此方法比以往节省90%以上的时间.     

Decoherence Effect and Beam Splitters for Production of Quasi-Amplified Entangled Quantum Optical Light

We let a set of beam splitters of vacuum mode with a chosen transmittance parameter η in interaction with a separable coherent states.This model induces the production of an attenuated quantum channels based on entangled optical states.Indeed,the decoherence effect is exploited positively here to generate such kind of quantum channels.Next,the amplitude damping and the entanglement amount of these produced channels are enhanced thereafter by a probabilistic quasi amplification process using again a 50 : 50 beam splitter.     

Quantum Transport through a Triple Quantum Dot System in the Presence of Majorana Bound States

We study the electron transport through a special quantum-dot(QD)structure composed of three QDs and two Majorana bound states(MBSs)using the nonequilibrium Green’s function technique.This QD-MBS ring structure includes two channels with the two coupled MBSs being Channel 1 and one QD being Channel 2,and three types of transport processes such as the electron transmission(ET),the Andreev reflection(AR),and the crossed Andreev reflection(CAR).By comparing the ET,AR,and CAR processes through Channels 1 and 2,we make a systematic study on the transport properties of the QD-MBS ring.It is shown that there appear two kinds of characteristic transport patterns for Channels 1 and 2,as well as the interplay between the two patterns.Of particular interest is that there exists an AR-assisted ET process in Channel 2,which is different from that in Channel 1.Thus a clear"X"pattern due to the ET and AR processes appears in the ET,AR,and CAR transmission coefficients.Moreover,we study how Channel 2 affects the three transport processes when Channel 1 is tuned in the ET and CAR regimes.It is shown that the transport properties of the ET,AR and CAR processes can be adjusted by tuning the energy level of the QD embedded in Channel 2.We believe this research should be a helpful reference for understanding the transport properties in the QD-MBS coupled systems.     

原子－光场精确解模型在绝热极限下的量子无损测量

研究了一个无损测量原子质心动量的精确可解模型，详细分析了无损测量的条件及无损测量的动力学过程。文中分析表明，绝热极限是实现此类模型无损测量的必要条件。最后针对此模型讨论了量子无损测量与表象之间的关系。     

Regularization of Quantum Relative Entropy in Finite Dimensions and Application to Entropy Production

The fundamental concept of relative entropy is extended to a functional that is regular-valued also on arbitrary pairs of nonfaithful states of open quantum systems. This regularized version preserves almost all important properties of ordinary relative entropy such as joint convexity and contractivity under completely positive quantum dynamical semigroup time evolution. On this basis a generalized formula for entropy production is proposed, the applicability of which is tested in models of irreversible processes. The dynamics of the latter is determined by either Markovian or non-Markovian master equations and involves all types of states.     

Off—Center D—Centers in a Quantum Dot in the Presence of a Perpendicular Magnetic Fields

We investigate the effect of the position of the donor in quantum dots on the energy spectrum in the presence of a perpendicular magnetic field by using the method of few-body physics,As a function of the magnetic field,we find,when D^- centers are placed sufficiently off-center,discontinuous ground-state transitions which are similar to those found in many-electron parabolic quantum dots.Series of magic numbers of angular momentum which minimize the ground-state electron-electron interaction energy have been discovered.The dependence of the binding energy of the gound-state of the D^- center on the dot radius for a few values of the magnetic field strength is obtained and compared with other results.     

Quantum Mechanical Effects in a Non-Dissipation Mesoscopic Coupled Circuit in the Presence of Source

Under the squeezed vacuum state, the quantum zero point fluctuations for both the charge and current of a non-dissipation mesoscopic coupled circuit in the presence of source are given. The quantum mechanical effects of this circuit at zero temperature are studied.     

Superinflation and Quintessence in the Presence of an Extra Field

We discuss the implication of the introduction of an extra field to the dynamics of a scalar field conformally coupled to gravitation in a homogeneous isotropic spatially flat universe. We show that for some reasonable parameter values the dynamical effects are similar to those of our previous model with a single scalar field. Nevertheless, for other parameter values new dynamical effects are obtained.     

Filamentation Instability in a Current‐Carrying Plasma in the Presence of Quantum Effects

The filamentation instability of a current‐carrying plasma under the diffusion condition is investigated taking into account the Bohm potential and the Fermi electron pressure. Using quantum hydrodynamic equations, the dispersion relation and growth rate of the instability is obtained. It is found that the filamentation instability, in the presence of quantum effects, depends on various characteristic parameters such as: electron Fermi velocity, plasma number density, ion thermal velocity and electron drift velocity. Moreover, the wavelength region in which the instability occurs is more restricted and the minimum size of filaments is larger, in comparison with the classical case. It is also found that the growth rate of the instability is smaller in the presence of quantum effects. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

（2+1）维动态黑洞的量子熵

在Tortoise坐标系中，利用brick-wall模型研究了来源于标量场的(2+1)维动态黑洞的量子熵.结果表明，在视界附近的薄区域内标量场的熵与黑洞熵有相同结构.特别是在静态情况下，量子熵满足熵的周长律. 关键词： 标量场 brick-wall模型 (2+1)维动态黑洞 量子熵     

无限深势阱下杂质量子点的能级计算

在有效质量近似下,垂直方向采用无限深势阱限制势,在x-y平面上,量子点内采用抛物势近似,在量子点边界处采用与实际情况更接近的无限深势阱.在中心杂质电荷为ηe时,利用波函数近似,得到基态和低激发态的能级,与x-y平面均采用抛物势时得到的能级进行了比较.计算发现在量子点真实半径比较小时,电子的基态和低激发态受其影响很大,而相应的能级随量子点的半径逐步增大.在量子点半径大于5倍有效玻尔半径时,能级受其影响已经变得很弱.并且,随着磁场的变化,量子点半径对基态和第一激发态的能级差的影响也很大.最后我们计算了杂质电子的基态束缚能并讨论了声子对其影响.