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Sep 18, 2013
09/13

by
D. B. Saakian

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The $P\to\infty$ limit was considered in the spherical P-spin glass. It is possible to store information in the vacuum configuration of ferromagnetic phase. Maximal allowed level of noise was calculated in ferromagnetic phase.

Source: http://arxiv.org/abs/cond-mat/9606034v1

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51

Sep 22, 2013
09/13

by
D. B. Saakian

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The evolution model with parallel mutation-selection scheme is solved for the case when selection is accompanied by base substitutions, insertions, and deletions. The fitness is assumed to be either a single-peak function (i.e., having one finite discontinuity) or a smooth function of the Hamming distance from the reference sequence. The mean fitness is exactly calculated in large-genome limit. In the case of insertions and deletions the evolution characteristics depend on the choice of...

Source: http://arxiv.org/abs/0908.1617v1

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205

Sep 19, 2013
09/13

by
D. B. Saakian

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A set of general physical principles is proposed as the structural basis for the theory of complex systems. First the concept of harmony is analyzed and its different aspects are uncovered. Then the concept of reflection is defined and illustrated by suggestive examples. Later we propose the principle of (random) projection of symmetrically expanded prereality as the main description method of complex systems.

Source: http://arxiv.org/abs/cond-mat/0102510v2

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48

Sep 22, 2013
09/13

by
D. B. Saakian

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An imitation of 2d field theory is formulated by means of a model on the hierarchic tree (with branching number close to one) with the same potential and the free correlators identical to those of 2d ones. Such a model possesses some features of original models for certain scale invariant theories. For the case of 2d conformal models it is possible to derive exact results. The renormalization group equation for the free energy is a reaction-diffusion equation, which is noise-free KPZ equation...

Source: http://arxiv.org/abs/physics/0111031v1

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56

Sep 22, 2013
09/13

by
D. B. Saakian

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We calculate moments of free energy's finite size correction for the transition point between ferromagnetic and spin glass phases. We find, that those moments scale with the number of spins with different critical indices, characteristic for the multiscaling. This critical point corresponds to threshold of errorless coding for a gaussian noisy channel. We are give the definition of statistical complexity using this free energy approach.

Source: http://arxiv.org/abs/cond-mat/0004406v1

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49

Sep 21, 2013
09/13

by
D. B. Saakian

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The complete phase diagram of Random Energy Model (REM) is obtained for complex temperatures using the method proposed by Derrida. We find the density of zeroes for statistical sum. Then the method is applied to Generalized Random Energy Model (GREM). This allows us to propose new analytical method for investigating zeroes of statistical sum for finite-dimensional systems.

Source: http://arxiv.org/abs/cond-mat/9905123v1

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103

Jul 20, 2013
07/13

by
D. B. Saakian

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We investigate the extreme value statistics connected with the dilute Random Energy Model with integer couplings. New universality class is found.

Source: http://arxiv.org/abs/cond-mat/9906103v2

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76

Sep 22, 2013
09/13

by
D. B. Saakian

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The results by E. Gardner and B.Derrida have been enlarged for the complex temperatures and complex numbers of replicas. The phase structure is found. There is a connection with string models and their phase structure is analyzed from the REM's point of view.

Source: http://arxiv.org/abs/cond-mat/0310549v1

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47

Sep 22, 2013
09/13

by
D. B. Saakian

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An imitation of 2d field theory is formulated by means of a model on the hierarhic tree (with branching number close to one) with the same potential and the free correlators identical to 2d correlators ones. Such a model carries on some features of the original model for certain scale invariant theories. For the case of 2d conformal models it is possible to derive exact results. The renormalization group equation for the free energy is noiseless KPZ equation with additional linear term.

Source: http://arxiv.org/abs/cond-mat/0111253v1

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64

Sep 23, 2013
09/13

by
D. B. Saakian

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In spin glass models one can remove minimization of free energy by some order parameter. One can consider hierarchy of order parameters. It is possible to divide energy among these parts. We can consider relaxation process in glass system phenomonologically, as exchange of energy between 2 parts. It is possible to identify trap points in phase space. We suggest some phenomonological approximation-truncated Langevine. The mean field statics is used to introduce a phenomenologic dynamics as its...

Source: http://arxiv.org/abs/cond-mat/9908309v1

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58

Sep 22, 2013
09/13

by
D. B. Saakian

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We consider spherical p-spin glass and p-spin glass models at imaginary temperatures. Imaginary temperatures are special case, when order parameters are real value numbers. Here there is a some antiferromagnetic like order.

Source: http://arxiv.org/abs/cond-mat/0111251v1

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Sep 22, 2013
09/13

by
D. B. Saakian

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It is possible to formulate 2d field theory on the ultrametric space with the free correlators identical to 2d correlators and the same potential. Such model should carry some features of original model for scale invariant theories. For the case of strings and 2d conformal models it is possible to derive exact results. It is possible to investigate not only bulk structure (phase transition points) of theory, but sometimes also correlators. Such ultrametric models could be naturally expressed...

Source: http://arxiv.org/abs/cond-mat/0004086v2

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51

Sep 23, 2013
09/13

by
D. B. Saakian

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A quadratic extension of REM has been treated. Discussed here is the origin of relation of REM to strings and other complex physical phenomena. Two basic features of the REM class of complex phenomena were identified: the double thermodynamic reflection (a hierarchy of free energies) including the strong reflection at the upper level (the free energy on the order of a logarithm of the degrees of freedom) and the loss (complete or partial) of the local symmetry property. Two main classes of...

Source: http://arxiv.org/abs/cond-mat/9908312v2

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95

Jul 20, 2013
07/13

by
D. B. Saakian

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A set of general physical principles is proposed as the structural basis for the theory of complex systems. First the concept of harmony is analyzed and its different aspects are uncovered. Then the concept of reflection is defined and illustrated by suggestive examples. Later we propose the principle of (random) projection of symmetrically expanded prereality as the main description method of complex systems.

Source: http://arxiv.org/abs/cond-mat/0009081v2

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66

Jul 20, 2013
07/13

by
A. E. Allahverdyan; D. B. Saakian

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The multi-access channels in quantum information theory are considered. Classical messages from independent sources, which are represented as some quantum states, are transported by a channel to one address. The messages can interact with each other and with external environment. After statement of problem and proving some general results we investigate physically important case when information is transported by states of electromagnetic field. One-way communication by noisy quantum channels...

Source: http://arxiv.org/abs/quant-ph/9712034v1

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40

Sep 20, 2013
09/13

by
A. E. Allahverdyan; D. B. Saakian

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We consider the problem of a state determination for a two-level quantum system which can be in one of two nonorthogonal mixed states. It is proved that for the two independent identical systems the optimal combined measurement (which considers the pair as one system) cannot be less optimal than the corresponding sequential one (local measurements, accompanying by transfer of classical information). The case of equality is achieved only when the mixed states have the same eigenvalues or the...

Source: http://arxiv.org/abs/quant-ph/9810057v1

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47

Sep 18, 2013
09/13

by
A. E. Allahverdyan; D. B. Saakian

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We have considered the two-spin interaction spherical spin-glass model with asymmetric bonds (coupling constants). Besides the usual interactions between spins and bonds and between the spins and a thermostat with temperature $T_{\sigma}$ there is also an additional factor: the bonds are not assumed random {\it a priori} but interact with some other thermostat at the temperature $T_{J}$. We show that when the bonds are frozen with respect to the spins a first order phase transition to a...

Source: http://arxiv.org/abs/cond-mat/9809170v1

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48

Sep 19, 2013
09/13

by
A. E. Allakhverdyan; D. B. Saakian

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We consider paramagnetic, spin-glass and ferromagnetic phases. At $T=0$ model gives for the some values of connectivity (near the critical) extremal suppression of finite size effects (decoding error probability).

Source: http://arxiv.org/abs/cond-mat/9506007v2

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58

Jul 20, 2013
07/13

by
A. E. Allahverdyan; D. B. Saakian

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The weak converse coding theorems have been proved for the quantum source and channel. The results give the lower bound for capacity of source and the upper bound for capacity of channel. The monotonicity of mutual quantum information have also been proved. PACS numbers: 03.65.Bz

Source: http://arxiv.org/abs/quant-ph/9702034v2

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58

Sep 21, 2013
09/13

by
A. E. Allahverdyan; D. B. Saakian

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The strengthened data processing inequality have been proved. The general theory have been illustrated on the simple example.

Source: http://arxiv.org/abs/quant-ph/9705036v1

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57

Sep 18, 2013
09/13

by
A. E. Allahverdyan; D. B. Saakian

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A strengthened Lindblad inequality has been proved. We have applied this result for proving a generalized $H$-theorem in non equilibrium thermodynamics. Information processing also can be considered as some thermodynamic process. From this point of view we have proved a strengthened data processing inequality in quantum information theory.

Source: http://arxiv.org/abs/cond-mat/9809127v1

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89

Sep 22, 2013
09/13

by
A. E. Allahverdyan; D. B. Saakian

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It is well known that quantum theory forbids the exact copying of an unknown quantum state. Therefore in broadcasting of classical information by a quantum channel an additional contribution to the error in the decoding is expected. We consider the optimal copying transformation which is adapted to classical information transmission by two linearly independent quantum states, and show that there is no additional contribution to the error. Instead the clones are correlated, and this breaks their...

Source: http://arxiv.org/abs/quant-ph/9805067v1

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133

Jul 20, 2013
07/13

by
D. B. Saakian; E. E. Vogel

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An approximate method is proposed for investigating complex-temperature properties of real-dimensional spin-glass models. The method uses the complex-temperature data of the ferromagnetic model on the same lattice. The universality line in the complex-temperature space is obtained.

Source: http://arxiv.org/abs/cond-mat/9906283v2

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54

Sep 22, 2013
09/13

by
A. E. Allahverdyan; D. B. Saakian

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We study adaptive control of classical ergodic Hamiltonian systems, where the controlling parameter varies slowly in time and is influenced by system's state (feedback). An effective adiabatic description is obtained for slow variables of the system. A general limit on the feedback induced negative entropy production is uncovered. It relates the quickest negentropy production to fluctuations of the control Hamiltonian. The method deals efficiently with the entropy-information trade off.

Source: http://arxiv.org/abs/0811.2531v1

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134

Sep 20, 2013
09/13

by
A. E. Allahverdyan; K. G. Petrosyan; D. B. Saakian

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We study feedback control of classical Hamiltonian systems with the controlling parameter varying slowly in time. The control aims to change system's energy. We show that the control problems can be solved with help of an adiabatic invariant that generalizes the conservation of the phase-space volume to control situations. New mechanisms of control for achieving heating, cooling, entropy reduction and particle trapping are found. The feedback control of a many-body system via one of its...

Source: http://arxiv.org/abs/cond-mat/0607222v1

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43

Sep 21, 2013
09/13

by
A. E. Allahverdyan; Th. M. Nieuwenhuizen; D. B. Saakian

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In a $p$-spin interaction spherical spin-glass model both the spins and the couplings are allowed to change in the course of time. The spins are coupled to a heat bath with temperature $T$, while the coupling constants are coupled to a bath having temperature $T_{J}$. In an adiabatic limit (where relaxation time of the couplings is much larger that of the spins) we construct a generalized two-temperature thermodynamics. It involves entropies of the spins and the coupling constants. The...

Source: http://arxiv.org/abs/cond-mat/9907090v1

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Sep 20, 2013
09/13

by
D. B. Saakian; E. Munoz; Chin-Kun Hu; M. W. Deem

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We use a path integral representation to solve the Eigen and Crow-Kimura molecular evolution models for the case of multiple fitness peaks with arbitrary fitness and degradation functions. In the general case, we find that the solution to these molecular evolution models can be written as the optimum of a fitness function, with constraints enforced by Lagrange multipliers and with a term accounting for the entropy of the spreading population in sequence space. The results for the Eigen model...

Source: http://arxiv.org/abs/q-bio/0608029v1