Based on a discussion of the theory experiment connection it is proposed to tighten the connection by replacing the real and complex number basis of physical theories by sets R_n, C_n of length m finite binary string numbers. Here n=n(t) will be cosmological time dependent. The form of the numbers in R_n is based on the infinite hierarchy of 2n figure outputs from measurements of any physical quantity with an infinite range (distance energy etc.). A space and time based on these numbers is described. It corresponds to an infinite sequence of spherical scale sections R_n,e(e an integer). Each section has the same number of points but the size increases exponentially with increasing e. The sections converge towards an origin which is a space singularity. Iteration of a basic order preserving transformation, F< or its inverse shows exponential expansion or contraction of the space with the origin as a source or sink of space points. The suitability of R_n space as a framework for inflationary cosmology is based on a constant iteration rate for F< and time dependent scale factors e and N=n(t). The time dependences restrict all space initially to a region of scale sections R_no,e with n_o (small) and e≤e_o (negative). Inflation which occurs naturally is stopped at a time when all points in the outermost Δ scale sections are expanding away from the origin at velocities >c. Then n increases to n_I > n_o where n_I is such that the outermost Δ scale sections of R_no space are contained in the scale section R_nI,o of R_nI space. This is needed if R_nI,o space is to be similar to the usual R space. Hubble expansion and the redshift are accounted for by a continuing slow increase in n. Comparison with experimental data suggests that the rate of increase must be at least one n unit every 30-60 million years.

This paper surveys joint work with Samson Abramsky. I will somewhat informally discuss the main results of a series of papers in a pedestrian not too technical way. These include: . 'The logic of entanglement', that is, the identification and abstract axiomatization of the 'quantum information-flow' which enables protocols such as quantum teleportation. To this means we define strongly compact closed categories which abstractly capture the behavioral properties of quantum entanglement. . 'Postulates for an abstract quantum formalism' in which classical information-flow (e.g. token exchange) is part of the formalism. As an example, we provide a purely formal description of quantum teleportation and prove correctness in abstract generality. In this formalism types reflect kinds contra the essentially typeless von Neumann formalism. Hence even concretely this formalism manifestly improves on the usual one. .'Towards a high-level approach to quantum informatics'. Indeed the above discussed work can be conceived as aiming to solve: ???/von Neumann quantum formalism ≈ high-level language/low-level language

Decoherence aiid dissipation of a quantum system occurs due to its entanglement with the environment (reservoir) . In the course of interaction of the system with the reservoir information about the system is 'recorded' in the state of the reservoir. This is why influence of the reservoir on the system (i.e. the system's decoherence and dissipation) may be accounted in the framework of quantum theory of continuous measurements. Constructing such a theory with the help of restricted path integrals (RPI) gives a model-independent theory of decoherence and dissipation. The special role of information in decoherence and dissipation is explicitly revealed by this approach. This makes it possible to apply the RPI approach for the analysis of decoherence in quantum informatic devices.

Quantum measurement is universal for quantum computation. Two models for performing measurement-based quantum computation exist: the one-way quantum computater was introduced by Briegel and Raussendorf and quantum computation via projective measurements only by Nielsen. The more recent development of this second model is based on state transfers instead of teleportation. From this development a finite but approximate quantum universal family of observables is exhibited which includes only one two-qubit observable while others are one-qubit observables. In this article an infinite but exact quantum universal family of observables is proposed including also only one two-qubit observable. The rest of the paper is dedicated to compare these two models of measurement-based quantum computation i.e. one-way quantum computation and quantum computation via projective measurements only. From this comparison which was initiated by Cirac and Verstraete closer and more natural connections appear between these two models. These close connections lead to a unified view of measurement-based quantum computation.

There are summarized our results obtained when studying the entangled electron-hole pairs by the direct and indirect electron paramagnetic resonance methods. These results demonstrate rather peculiar response of the spins in the entangled state to the manipulations with the external microwave fields: intensities of lines in the electron paramagnetic resonance spectra should oscillate; the echo type signal is expected as the response to only one microwave pulse; the primary spin echo signal has anomalous phase compared to the phase of the echo signal in a case of spins in a non-entangled state; the two-quantum transitions can be manifested even in the absence of the spin-spin interaction if the electron paramagnetic resonance is detected indirectly, e.g., optically. A possible scenario for the quantum teleportation experiment is suggested.

In this paper, we present a universal control technique, the non-holonomic control, which allows us to impose any arbitrarily prescribed unitary evolution to any quantum system through the alternate application of two well-chosen perturbations.

In this paper, we show how the non-holomic control technique can be employed to build completely controlled quantum devices. Examples of such controlled structures are provided.

In this paper, we present a coherence protection method based upon a multidimensional generalization of the Quantum Zeno Effect, as well as ideas from the coding theory. The non-holonomic control technique is employed as a physical tool which allows its effective implementation. The two limiting cases of small and large quantum systems are considered.

In this paper, we present a realistic application of the coherence protection method proposed in the previous article. A qubit of information encoded on the two spin states of a Rubidium isotope is protected from the action of electric and magnetic fields.

In the talk we present results on comparitve power of classical and quantum computational models. We focus on two well known in Computer Science models: finite automata which is known as uniform computational model and branching programs which is known as nonuniform computational model.

We present a classical probabilistic simulation technique of quantum Turing machines As a corollary of this technique we obtain several results on relationship among classical and quantum complexity classes such as: PrQP PP BQP PP and PrQSPACE(S(n)) PrPSPACE(S(n)).

We have analyzed and measured the quantum coherent dynamics of a circuit containing two coupled superconducting charge qubits. Each qubit is based on a Cooper pair box connected to a reservoir electrode through a Josephson junction. Two qubits are coupled electrostatically by a small island overlapping both Cooper pair boxes. Quantum state manipulation ofthe qubit circuit is done by applying non-adiabatic voltage pulses to the common gate. We read out each qubit by means of probe electrodes connected to Cooper pair boxes through high-Ohmic tunnel junctions. With such a setup the measured pulse-induced probe currents are proportional to the probability for each qubit to have an extra Cooper pai1r after the manipulation. As expected from theory and observed experimentally the measured pulse-induced current in each probe has two frequency components whose position on the frequency axis can be externally controlled. This is a result ofthe inter-qubit coupling which is also responsible for the avoided level crossing that we observed in the qubits' spectra. Our simulations show that in the absence of decoherence and with a rectangular pulse shape the system remains entangled most ofthe time reaching maximally entangled states at certain instances.

Quantum spin models describe quantum magnetism in Solid-State systems. Even when some of these models were proposed at the very beginning of quantum mechanics their study is hindered by the fact that they are very difficult to be studied numerically. Quantum computers could allow us to solve this problem because they can be used for the efficient simulation of many-body quantum systems. In our work we propose an alternative that is easier than quantum computation. By means of lasers a set of trapped ions can simulate the physics of interacting spins in such a way that the range and the sign of the interactions can be tuned by the choice of lasers and trapping conditions. Our proposal can be applied to the simulation of Ising XY and Heisenberg models.

The coherent quantum dynamics of an electron in the quantum-dot ring structure under the resonant electromagnetic pulse is studied theoretically. A possibility of the selective electron transfer between any two dots is demonstrated. The transfer probability as a function of the pulse and dot parameters is calculated. It is shown that this probability can be close to unity. The factors lowering the transfer probability in the real system are discussed. The results obtained may be used in the engineering of novel nanoelectronic devices for quantum bits processing.

The idea of the quantum computation is based on paradoxical principles of quantum physics superposition and entanglement of quantum states. This idea looks well-founded on the microscopic level in spite of the absence of an universally recognized interpretation of these paradoxical principles since they were corroborated over and over again by reliable experiments on the microscopic level. But the technology can not be able in the near future to work on the microscopic level. Therefore macroscopic quantum phenomenon-superconductivity is very attractive for the realization of the idea of quantum computer. It is shown in the present paper that a chain of superconducting loops can be only possible quantum register. The proposals by some authors to provide the EPR correlation with help of a classical interaction witness the misunderstanding of the entanglement essence. The problem of the possibility of superposition of macroscopically distinct states is considered.

It is considered the indirect inter-qubit coupling in 1D chain of atoms with nuclear spins 1/2 which plays role of qubits fin the quantum register. This chain of the atoms is placed by regular way in easy-axis 3D antiferromagnetic thin plate substrate which is cleaned from the other nuclear spin containing isotopes. It is shown that the range of indirect inter-spin coupling may run to a great number of lattice constants both near critical point of quantum phase transition in antiferromagnet of spin-flop type (control parameter is external magnetic field) and/or near homogeneous antiferromagnetic resonance (control parameter is microwave frequency).

We consider a new approach of the SU(3)-symmetry polarization in Hubert space for a quantum Bose-system with internal Gell-Mann symmetry in quantum and atomic optics. The operational determination of the SU(3) phase problem for a three mode optical field is discussed for the first time. The original twelve-port interferometer for simultaneous measurements of both the Gell-Mann parameters and the phase characteristics is proposed. The signal-to-noise ratio coefficients for coherent end entangled states of light are examined. In the paper we also discuss application ofour theory for the problems of quantum information as well.

Generation of multi-photon states (such as for instance three- and four-photon states) is one of the most challenging problems of modern quantum optics. In many works the authors claim to have produced such states by means of overlapping photon pairs generated in spontaneous parametric down-conversion (SPDC). Moreover three- and four-photon states generated this way have been used for observing Greenberger-Horne-Zeilinger (GHZ) polarization states testing Bell's inequalities for spin-1 quantum systems preparing W-states and other applications. In this paper we show that the criterion for obtaining three- or four-photon states is the behavior of the corresponding normalized Glauber's correlation function. Calculations carried out for the case of SPDC or even PDC in the stimulated regime demonstrate that these processes are not capable of generating three- or four-photon states: photon statistics reveals typically two-photon behaviour. We suggest a method of measuring higher-order correlation functions in the pulsed regime which allows one to study multi-photon correlations for these and many other processes.

What obstructs the realization of useful quantum cryptography is single photon scheme or entanglement which is not applicable to the current infrastructure of optical communication network. We are concerned with the following question: Can we realize the information theoretically secure symmetric key cipher under "the finite secret key" based on quantum-optical communications? A role of quantum information theory is to give an answer for such a question. As an answer for the question a new quantum cryptography was proposed by H. P. Yuen which can realize a secure symmetric key cipher with high speeds(Gbps) and for long distance(1000 Km). Although some researchers claim that Yuen protocol(Y-OO) is equivalent to the classical cryptography they arc all mistaken. Indeed it has no classical analogue and also provides a generalization even in the conventional cryptography. At present it is proved that a basic model of Y-OO has at least the security such as H(X/Y_E)=H(K/Y_E)=H(K), H(K/Y_E,X)~0 under the average photon number per signal light pulse:<n>~10000. Towards our final goal in this paper we clarify a role of classical randomness(secret key) and quantum randomness in Y-OO and give a rigorous quantum mechanical interpretation of the security showing an analysis of quantum collective attack.

We give formulations of the famous additivity conjecture for several important quantities characterizing quantum channel and prove their global equivalence to the additivity of the classical capacity of a channel under input constrains (like mean energy constrain).

The novel experimental realization of three-state optical quantum systems is presented. We use the polarization state of biphotons in single frequency- and spatial mode to generate an arbitrary qutrits. In particular the specific sequence of states that are used in the extended version of BB84 quantum key distribution protocol was generated and tested. We experimentally verify the orthogonality of the 12 basic states and demonstrate the ability of switching between them. The tomography procedure is applied to reconstruct the density matrices of generated states.

A new Quantum cryptography protocols with several bases and infinite number of bases is proposed. This work considers with the idea of enlarging number of bases. The first part of the work presents an experimental realization of two three and six bases protocols. Then principle of enlarging of the bases number leads to the infinite number of bases or to the floating basis protocol. This protocol requires existence of some secret key. This key helps to make Alice's and Bob's bases coincide. So the transmission becomes twice faster and restricts ofthe mean photon number becomes lower.

The χ-function (the Holevo capacity of constrained channel) and the convex closure of the output entropy for arbitrary infinite dimensional channel are considered. The properties of the χ-function and of the convex closure of the output entropy are explored. The applications of the obtained results to the additivity problem and to the theory of entanglement are presented.

Possibilities of improving characteristics of quantum key distribution (QKD) protocols via variation of character set in quantum alphabets are investigated. QKD protocols with discrete alphabets letters of which form regular polyhedrons on the Bloch sphere (tetrahedron octahedron cube icosahedron and dodecahedron which have 4, 6, 8, 12, and 20 vertexes) and QKD protocol with continuous alphabet which corresponds to the limiting case of a polyhedron with infinitive number of vertexes are considered. Stability of such QKD protocols to the interceptresend and optimal eavesdropping strategies at the individual attacks is studied in detail. It is shown that in case of optimal eavesdropping strategy after safety bases reconciliation critical error rate of the QKD protocol with continuous alphabet surpasses all other protocols. Without basis reconciliation the highest critical error rate have the protocol with tetrahedron-type alphabet.

Quantum Fourier transform (QFT) is an important subroutine in quantum computation. A QFT followed by measurement (MQFT) which appears in the final part of the phase estimation algorithm was demonstrated on a simple circuit based on fiber-optics. The MQFT was shown to be robust against imperfections in the rotation gate. Error probability was estimated to be 0.01 per qubit but could be further reduced by taking the majority of the accumulated results. The reduction of error probability resulted in a successful MQFT of 1024 qubits. The present results not only demonstrate the potential of fiber optics but provide an important clue for quantum computer design.

Whereas quantum cryptography ensures security by virtue of complete indistinguishability of nonorthogonal quantum states attenuation in quantum communication channels and unavailability of single-photon sources present major problems. In view of these difficulties the security of quantum cryptography can change from unconditional to conditional. Since the restrictions imposed by nonrelativistic quantum mechanics and used to formulate key distribution protocols are largely exhausted new principles are required. The fundamental relativistic causality principle in quantum cryptography can be used to propose a new approach to ensuring unconditional security of quantum cryptosystems that eliminates the aforementioned difficulties. Quantum cryptosystems of this kind should obviously be called relativistic. It is shown that relativistic quantum cryptosystems remain unconditionally secure: first attenuation in a quantum communication channel can only reduce the key generation rate but not the security of the key second the source may not generate pure single-photon states and a nonzero single-photon probability will suffice. The scheme remains secure even if the contribution of a single-photon component is arbitrarily small. This formally implies that a state may be characterized by an arbitrarily large mean photon number. The single-photon probability affects only the key generation rate but not security.

Possibilities of improving critical error rate of quantum key distribution (QKD) protocols for different strategies of eavesdropping are investigated. QKD-protocols with discrete alphabets letters of which form regular polyhedrons on the Bloch sphere (tetrahedron octahedron cube icosahedron and dodecahedron which have 4, 6, 8, 12 and 20 vertexes respectively) and QKD-protocol with continuous alphabet which corresponds to the limiting case of a polyhedron with infinitive number of vortexes are considered. Stability of such QKD-protocols to the noise in a quantum channel which is due to the Eve's interference that apply either intercept-receipt or optimal eavesdropping strategy at the individual attacks is studied in detail. It is shown that in case of optimal eavesdropping strategy after bases reconciliation the QKD-protocol with continuous alphabet surpasses all other protocols in terms of noise-resistance. Without basis reconciliation the highest critical error rate have the protocol with tetrahedron-type alphabet.

Nowadays the task of molecular modeling plays the important role in many branches of science and engineering. But the existing models do not take quantum effects into account because of known calculating issues. The main difficulty in modeling of the evolution of multi particle quantum states by solving the Schroedinger equation consists iii exponential growth of required time and memory with the corresponding increase of entangled particles. The approach to this problem considered in works [3 4] consists in applying Feynman path integrals instead of solving Schroedinger equation. In terms of the "amplitude quanta" method based on this approach the wave function of a particle is calculated as a sum of the large amount of a.q. that probably will allow the linear growth of required memory with the corresponding increase of entangled particles. This approach also allows to the easy transition from the classical description of a particle to the quantum and back. The given work is devoted to the development of the quantum state evolution model based on the a. q. method in one and two-dimensional cases.

We represent program for the simulation of evolution one and the two-particle quantum systems on the classical computer. Program is the part of the work of our department on the program packet of simulation. Simulation is produced by the numerical solution of the Schroedinger equation with the use of finite difference schemes.

Based on standard Umkehr inversion algorithm, the ozone vertical profiles have been retrieved from the Dobson Umkehr observations of Beijing. The corrections are made for aerosols in the process of inversion, and the retrieved results have been improved. By using the derived profiles, the characteristics and trends of ozone vertical distributions of Beijing during 1990-2002 are studied. The results imply that the ozone concentrations between 10.3 and 23.5km were unusually low during the fall of 1992 and the spring of 1993, and at the same time, the total ozone underwent a marked decline. During the period 1990-2002, the total ozone decreased slightly, but the trends of change of ozone concentrations at different altitudes were different.

In the n-type silicon alloyed by phosphorus and compensated by zinc on a background wide and intensive Lorentz lines the narrow undistinguished signal have been discovered. In a narrow interval ol magnetic fields it finds out thin SF1 structure. It is characterize for the ionic pair which are taking placc in triplet condition. The mathematical analysis of spectrum EPR of the second signal specifies formatior of the individual ionic pair formed spin-free by neutral zinc atom and positively charged ion phosphorus (spin S=1/2). From dipole constants follows that the distance between zinc atom and phosphorus in ionic pair makes about 10Å (two nuclear distances of silicon). Temperature dependence of spectrum EPR of this ionic specifies pairs appreciable increase in distance in it at temperatures below 183K that apparently is caused by phase transition in a vicinity of this pair. Spectral parameters of ionic pair Zn-P are determined.

The numerical analysis of the vacuum nanotriode model with three nanopillar field emifters is carried out. This analysis shows that fluctuation in transconductance of nanotriode can be explained with the assumption that three nanopillar field emitters are three sources of mutually coherent electron waves. The interference picture in the grid plane (in the gate aperture) varies depending on potential of a grid. Thereof the anode current of nanotriode oscillates. The transconductance dependence calculated on this model coincides with an experimental curve. It is shown that nanotriode with the opened aperture in the anode and with the second continuous anode-drain electrode at distances from 100 nanometers up to 1 mm from the first anode with an aperture will enable to demonstrate precise interference fluctuations in the current-voltage characteristic with amplitude on 2 orders more than in existing experiments. Such scheme of nanotriode will enable to receive the change of a sign on function in transconductance of nanotriode. In this case current-voltage characteristic of nanotriode will be N-shaped as in tunnel diode. This experiment will prove also that in the vacuum nanotriode the length of coherence of electrons in a tungsten wire of 2 nanometers in diameter at room temperature exceeds the sum of lengths of two lateral field emitters plus the distance between their bases (~5Onm).