Topological Properties of the Born–Oppenheimer Approximation and Implications for the Exact Spectrum

The Born–Oppenheimer approximation can generally be applied when a quantum system is coupled with another comparatively slower system which is treated classically: for a fixed classical state, one considers a stationary quantum vector of the quantum system. Geometrically, this gives a vector bundle over the classical phase space of the slow motion. The topology of this bundle is characterized by integral Chern classes. In the case where the whole system is isolated with a discrete energy spectrum, we show that these integers have a direct manifestation in the qualitative structure of this spectrum: the spectrum is formed by groups of levels and these integers determine the precise number of levels in each group.     

Theoretical Study of the Electronic and Transport Properties of Lateral 2D–1D–2D Graphene–CNT–Graphene Structures

JETP Letters - The electronic and transport properties of new hybrid 2D–1D–2D structures of carbon atoms, which are graphene sheets continuously connected through a fragment of a...     

Changes in the Properties of Iron during BCC–FCC Phase Transition

Physics of the Solid State - The thermodynamic properties of bcc and fcc iron phases are calculated at the temperature of the polymorphic bcc–fcc phase transition using the method of...     

The Influence of Dimesions and Phase State of Structural Elements on Mechanical Properties of Binary Alloys of the Ti–Nb and Zr–Nb Systems

Russian Physics Journal - The results of investigation of the influence of the structural element size and phase state of the Ti – 45 wt.% Nb and Zr – 1 wt.% Nb binary alloys on their...     

Mellin–Barnes Representation of the Topological String

We invoke integrals of Mellin–Barnes type to analytically continue the Gopakumar–Vafa resummation of the topological string free energy in the string coupling constant, leading to additional non-perturbative terms. We also discuss in a similar manner the refined and Nekrasov–Shatashvili limit version thereof. The derivation is straight-forward and essentially boils down to taking residue. This allows us to confirm some related conjectures in the literature at tree-level.     

On the Orthocomplementation of State–Property–Systems of Contextual Systems

We adopt an operational approach to quantum mechanics in which a physical system is defined by the mathematical structure of its set of states and properties. We present a model in which the maximal change of state of the system due to interaction with the measurement context is controlled by a parameter which corresponds with the number N of possible outcomes in an experiment. In the case N=2 the system reduces to a model for the spin measurements on a quantum spin-1/2 particle. In the limit N→∞ the system is classical, i.e. the experiments are deterministic and its set of properties is a Boolean lattice. For intermediate situations the change of state due to measurement is neither ‘maximal’ (i.e. quantum) nor ‘zero’ (i.e. classical). We show that two of the axioms used in Piron’s representation theorem for quantum mechanics are violated, namely the covering law and weak modularity. Next, we discuss a modified version of the model for which it is even impossible to define an orthocomplementation on the set of properties. Another interesting feature for the intermediate situations of this model is that the probability of a state transition in general not only depends on the two states involved, but also on the measurement context which induces the state transition.     

Effect of Common-Cation CdBVI Compounds on the Properties of Solid Solutions of ZnS–CdBVI Systems

Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques - Solid solutions of ZnS–CdBVI systems (B = S, Se, Te), identified as substitutional solid solutions with the...     

A Geometric Analysis of the Effects of Noise on Berry Phase

In this work we describe the effect of classical and quantum noise on the Berry phase. It is not a topical review article but rather an overview of our work in this field aiming at giving a simple pictorial intuition of our results.     

Detection of the Ferromagnetic Properties of Si:P in the Region of an Insulator–Metal Phase Transition

JETP Letters - The ferromagnetic properties of Si:P in the region of a concentration insulator–metal phase transition at liquid helium temperatures have been detected and studied. To...     

Electron–Hole Dimers in the Parent Phase of Quasi–2D Cuprates

Physics of the Solid State - The key feature of parent cuprates of the La2CuO4 type, in addition to their high ionic polarizability and closeness to polarization catastrophe, is identified as their...     

Roles of Elements of a Heterostructure Based on the Topological Phase of Hg1 – xCdxTe in the Effect of PT-Symmetric Terahertz Photoconductivity

JETP Letters - It is demonstrated that the PT-symmetric terahertz photoconductivity observed in heterostructures based on thick Hg1 – xCdxTe films in the topological phase is due to the...     

Studying the Optical Properties of Hexogen–Aluminum Composites

A theoretical study is carried out within the framework of density matrix formalism of the error signal slope for frequency standards based on the resonance of saturated absorption excited in the field of two counterwaves. Two schemes of error-signal formation are considered: in the first case, the frequency of only the test field is modulated, and, in the second case, the frequency modulation of both waves is carried out. On the basis of the calculations, the optimal parameters of harmonic modulation are determined, at which the slope has the maximum value.     

Extensive Properties of the Complex Ginzburg–Landau Equation

We study the set of solutions of the complex Ginzburg-Landau equation in R^d, d <3. We consider the global attracting set (i.e., the forward map of the set of bounded initial data), and restrict it to a cube Q_L of side L. We cover this set by a (minimal) number N_QL(l) of balls of radius l in $L^infin(Q_L). We show that the Kolmogorov l-entropy per unit length, $L^infin(Q_L). We show that the Kolmogorov l-entropy per unit length, H_\epsilon =\lim_{L\to\infty} L^{-d} \logtwo N_{Q_L}(\epsilon)< /FORMULA > exists. In particular, we bound < FORMULA FORM=ÏNLINE» exists. In particular, we bound H_\epsilon< /FORMULA > by < FORMULA FORM=ÏNLINE» by \OO\bigl(\logtwo(1/\epsilon )\bigr)< /FORMULA > , which shows that the attracting set is < SMALL > smaller < /SMALL > than the set of bounded analytic functions in a strip. We finally give a positive lower bound: < FORMULA FORM=ÏNLINE», which shows that the attracting set is smaller than the set of bounded analytic functions in a strip. We finally give a positive lower bound: H_\epsilon>\OO\bigl (\logtwo(1/\epsilon)\bigr)$.     

Ab Initio Study of the Structural Properties of the Co–Ni–Sn Heusler Alloys

Physics of the Solid State - The ab initio investigations of the structural and magnetic properties of the Co2Ni1&nbsp;+&nbsp;xSn1&nbsp;–&nbsp;x (x&nbsp;=&nbsp;0,...     

Robustness of Quantum Cryptography Systems with Phase–Time Coding against Active Probing Attacks

Journal of Experimental and Theoretical Physics - The robustness of a quantum cryptography system is considered that uses a protocol with phase–time coding on attenuated coherent states. This...     

Light-Front Quantization of the Chern–Simons–Higgs Theory in the Broken Symmetry Phase

Two-space one-time dimensional Chern–Simons–Higgs theory is quantized on the light-front in the broken (frozen) symmetry phase of the Higgs potential.     

Physical Properties of Solid Solutions InxAl1–xN

Russian Physics Journal - The phase diagrams and the results of studies of the GaN, AlN and InN ternary solid solutions grown using the magnetron sputtering, molecular beam epitaxy, and...