Quadratic kinetic equations are linear in the tensor product space

It is shown that quadratic kinetic equations are linear in the tensor product space.     

Continuous tensor product states which are translation invariant but not quasi-free

We show how the theory of continuous tensor products can be used to construct, for commutation relations, translation invariant but not quasi-free states as continuous tensor products of states for systems with one degree of freedom.     

Quantum potential and the spatial distribution of observable values

Quantum potential theory points to the possibility and usefulness of assigning values of the momentum observable at each point on the configuration space. We give a formulation of such an idea for all observables together with an analysis of the meaning of such local values within quantum mechanics. The formulation is easily extended to obtain generalised phase space distributions.     

Quantum effects,inflationary model,and observable universe

The very early stages of evolution of the universe might have a profound implications for its further, evolution and presently, observed large scale structure. It is shown that if the universe passed through an inflationary phase after the quantum stage then the effects of quantum gravity have been washed out and the presently observed distribution of matter is a consequence of processes occurring during and after the inflationary phase.     

Quantum forms of tensor products

We describe the skew tensor-product structure inherent to Yang-Mills procedures pertaining to non-commutative spaces obtained by (skew) tensorization.Dedicated to Huzihiro Araki     

量子Turbo乘积码

量子通信是经典通信和量子力学相结合的一门新兴交叉学科.量子纠错编码是实现量子通信的关键技术之一.构造量子纠错编码的主要方法是借鉴经典纠错编码技术,许多经典的编码技术在量子领域中都可以找到其对应的编码方法.针对经典纠错码中最好码之一的Turbo乘积码,提出一种以新构造的CSS型量子卷积码为稳定子码的量子Turbo乘积码.首先,运用群的理论及稳定子码的基本原理构造出新的CSS型量子卷积码稳定子码生成元,并描述了其编码网络.接着,利用量子置换SWAP门定义推导出量子Turbo乘积码的交织编码矩阵.最后,推导出量子Turbo乘积码的译码迹距离与经典Turbo乘积码的译码距离的对应关系,并提出量子Turbo乘积码的编译码实现方案.这种编译码方法具有高度结构化,设计思路简单,网络易于实施的特点. 关键词： CSS码 量子卷积码 量子Turbo乘积码 量子纠错编码     

A relative tensor product of subfactors over a modular tensor category

We define and study a certain relative tensor product of subfactors over a modular tensor category. This gives a relative tensor product of two completely rational heterotic full local conformal nets with trivial superselection structures over a common chiral representation category. In particular, we have a new realization of fusion rules of modular invariants. This also gives a mathematical definition of a composition of two gapped domain walls between topological phases.     

Quantum structures 1

Introduction

Quantum structures 1     

Conjugation properties of tensor product and fusion coefficients

We review some recent results on properties of tensor product and fusion coefficients under complex conjugation of one of the factors. Some of these results have been proven, some others are conjectures awaiting a proof, one of them involving hitherto unnoticed observations on ordinary representation theory of finite simple groups of Lie type.     

Quantum structures in macroscopic reality

We show that it is possible to construct macroscopic entities that entail a quantum logical structure. We do this by means of the introduction of a simple macroscopic entity and study its structure in terms of lattices and graphs, and show that the lattice is non-Boolean.     

Quantum phase transitions in matrix product systems

We investigate quantum phase transitions (QPTs) in spin chain systems characterized by local Hamiltonians with matrix product ground states. We show how to theoretically engineer such QPT points between states with predetermined properties. While some of the characteristics of these transitions are familiar, like the appearance of singularities in the thermodynamic limit, diverging correlation length, and vanishing energy gap, others differ from the standard paradigm: In particular, the ground state energy remains analytic, and the entanglement entropy of a half-chain stays finite. Examples demonstrate that these kinds of transitions can occur at the triple point of "conventional" QPTs.     

Quantum Logics that are Symmetric-difference-closed

International Journal of Theoretical Physics - In this note we contribute to the recently developing study of “almost Boolean” quantum logics (i.e. to the study of orthomodular...     

On the tensor product of representations of semisimple Lie groups

All topologically irreducible representations involved in the tensor product of finite and infinite dimensional representations of the Principal nonunitary series (including the unitary series) of a semisimple Lie group are defined.     

Quantum structures for multiband photon detection

The work describes multiband photon detectors based on semiconductor micro-and nano-structures. The devices considered include quantum dot, homojunction, and heterojunction structures. In the quantum dot structures, transitions are from one state to another, while free carrier absorption and internal photoemission play the dominant role in homo or heterojunction detectors. Quantum dots-in-a-well (DWELL) detectors can tailor the response wavelength by varying the size of the well. A tunnelling quantum dot infrared photodetector (T-QDIP) could operate at room temperature by blocking the dark current except in the case of resonance. Photoexcited carriers are selectively collected from InGaAs quantum dots by resonant tunnelling, while the dark current is blocked by AlGaAs/InGaAs tunnelling barriers placed in the structure. A two-colour infrared detector with photoresponse peaks at ∼6 and ∼17 μm at room temperature will be discussed. A homojunction or heterojunction interfacial workfunction internal photoemission (HIWIP or HEIWIP) infrared detector, formed by a doped emitter layer, and an intrinsic layer acting as the barrier followed by another highly doped contact layer, can detect near infrared (NIR) photons due to interband transitions and mid/far infrared (MIR/FIR) radiation due to intraband transitions. The threshold wavelength of the interband response depends on the band gap of the barrier material, and the MIR/FIR response due to intraband transitions can be tailored by adjusting the band offset between the emitter and the barrier. GaAs/AlGaAs will provide NIR and MIR/FIR dual band response, and with GaN/AlGaN structures the detection capability can be extended into the ultraviolet region. These detectors are useful in numerous applications such as environmental monitoring, medical diagnosis, battlefield-imaging, space astronomy applications, mine detection, and remote-sensing. The paper presented there appears in Infrared Photoelectronics, edited by Antoni Rogalski, Eustace L. Dereniak, Fiodor F. Sizov, Proc. SPIE Vol. 5957, 59570W (2005).     

Quantum interference in artificial band structures

Magnetotransport experiments on two-dimensional electron systems with an atomically precise, one-dimensional potential modulation reveal striking quantum interference oscillations. Within a semiclassical framework, they are recognized either as self-interference along closed orbits, many of them rendered possible by magnetic breakdown between Fermi contour segments of the artificial band structure, or as interference-enhanced backscattering. The known commensurability oscillations appear as a special case of the latter mechanism.     

On the reduction ofn-fold tensor product representations of noncompact groups

The reduction ofn-fold tensor products of induced unitary representations of noncompact groups into irreducible constituents is shown. Clebsch-Gordon coefficients are then calculated. The technique is applied to then-fold tensor products of the positive mass representations of the Poincaré group.