Institute of Physics and Technology

Almaty, Kazakhstan

Institute of Physics and Technology

Almaty, Kazakhstan
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Ganbold G.,Institute of Physics and Technology
EPJ Web of Conferences | Year: 2017

Main properties of stable quark-Antiquark bound states have been investigated by using a relativistic quark model with analytic confinement. A new insight into the problem of hadron mass generation is provided. It has been shown that the compositeness condition expressing the Yukawa coupling of the meson-quark interaction and the master equation relating the meson mass function to the Fermi coupling can together guarantee the equivalency of the both theories, thereby providing an interpretation of the meson field as a bound state of constituent quarks. A smooth behavior for the Fermi coupling G(M) obeying reasonable accuracy for the meson estimated masses M has been obtained. We have also updated our previous numerical results for the weak-decay constants as well as the electromagnetic decay widths of mesons. The obtained estimates are found in reasonable agreement with the recent experimental data. © The Authors, published by EDP Sciences, 2017.


News Article | December 12, 2016
Site: www.eurekalert.org

Scientists from the Institute of Physics and Technology of the Russian Academy of Sciences and MIPT have let two electrons loose in a system of quantum dots to create a quantum computer memory cell of a higher dimension than a qubit (a quantum bit). In their study published in Scientific Reports, the researchers demonstrate for the first time how quantum walks of several electrons can help to implement quantum computation. "By studying the system with two electrons, we solved the problems faced in the general case of two identical interacting particles. This paves the way toward compact high-level quantum structures," comments Leonid Fedichkin, Expert at the Russian Academy of Sciences, Vice-Director for Science at NIX (a Russian computer company), and Associate Professor at MIPT's Department of Theoretical Physics. In a matter of hours, a quantum computer would be able to hack through the most popular cryptosystem used even in your web browser. As far as more benevolent applications are concerned, a quantum computer would be capable of molecular modeling that takes into account all interactions between the particles involved. This in turn would enable the development of highly efficient solar cells and new drugs. To have practical applications, a quantum computer needs to incorporate hundreds or even thousands of qubits. And that is where it gets tricky. As it turns out, the unstable nature of the connection between qubits remains the major obstacle preventing us from using quantum walks of particles for quantum computation. Unlike their classical analogs, quantum structures are extremely sensitive to external noise. To prevent a system of several qubits from losing the information stored in it, liquid nitrogen (or helium) needs to be used for cooling. Plenty of schemes have been proposed for the experimental realization of a separate qubit. In an earlier study, a research team led by Prof. Fedichkin demonstrated that a qubit could be physically implemented as a particle "taking a quantum walk" between two extremely small semiconductors known as quantum dots, which are connected by a "quantum tunnel." From the perspective of an electron, the quantum dots represent potential wells. Thus, the position of the electron can be used to encode the two basis states of the qubit--|0? and |1?--depending on whether the particle is in one well or the other. Rather than sit in one of the two wells, the electron is smeared out between the two different states, taking up a definite position only when its coordinates are measured. In other words, it is in a superposition of two states. If an entangled state is created between several qubits, their individual states can no longer be described separately from one another, and any valid description must refer to the state of the whole system. This means that a system of three qubits has a total of 8 basis states and is in a superposition of them: A|000?+B|001?+C|010?+D|100?+E|011?+F|101?+G|110?+H|111?. By influencing the system, one inevitably affects all of the 8 coefficients, whereas influencing a system of regular bits only affects their individual states. By implication, n bits can store n variables, while n qubits can store 2? variables. Qudits offer an even greater advantage, since n four-level qudits (aka ququarts) can encode 4?, or 2?×2? variables. To put this into perspective, 10 ququarts store approximately 100,000 times more information than 10 bits. With greater values of n, the zeros in this number start to pile up very quickly. In this study, Alexey Melnikov and Leonid Fedichkin obtain a system of two qudits implemented as two entangled electrons quantum-walking around the so-called cycle graph. To make one, the scientists had to "connect the dots" forming a circle (once again, these are quantum dots, and they are connected by the effect called quantum tunneling). The entanglement of the two electrons is caused by the mutual electrostatic repulsion experienced by like charges. It is possible to create a system of even more qudits in the same volume of semiconductor material. To do this, it is necessary to connect quantum dots in a pattern of winding paths and have more wandering electrons. The quantum walks approach to quantum computation is convenient because it is based on a natural process. Nevertheless, the presence of two identical electrons in the same structure was a source of additional difficulties that had remained unsolved. The phenomenon of particle entanglement plays a pivotal role in quantum information processing. However, in experiments with identical particles, it is necessary to distinguish so-called false entanglement, which can arise between electrons that are not interacting, from genuine entanglement. To do this, the scientists performed mathematical calculations for both cases, viz., with and without entanglement. They observed the changing distribution of probabilities for the cases with 6, 8, 10, and 12 dots, i.e., for a system of two qudits with three, four, five, and six levels each. The scientists demonstrated that their proposed system is characterized by a relatively high degree of stability. It has been a long time since people first set their hearts on building a universal quantum computer, but so far we have been unable to connect a sufficient number of qubits. The work of the Russian researchers brings us one step closer to a future where quantum computations are commonplace. And although there are algorithms that quantum computers could never accelerate, others would still benefit enormously from devices able to exploit the potential of large numbers of qubits (or qudits). These alone would be enough to save us a couple of thousand years.


Home > Press > Two electrons go on a quantum walk and end up in a qudit: Russian scientists find a way to reliably connect quantum elements Abstract: Scientists from the Institute of Physics and Technology of the Russian Academy of Sciences and MIPT have let two electrons loose in a system of quantum dots to create a quantum computer memory cell of a higher dimension than a qubit (a quantum bit). In their study published in Scientific Reports, the researchers demonstrate for the first time how quantum walks of several electrons can help to implement quantum computation. "By studying the system with two electrons, we solved the problems faced in the general case of two identical interacting particles. This paves the way toward compact high-level quantum structures," comments Leonid Fedichkin, Expert at the Russian Academy of Sciences, Vice-Director for Science at NIX (a Russian computer company), and Associate Professor at MIPT's Department of Theoretical Physics. In a matter of hours, a quantum computer would be able to hack through the most popular cryptosystem used even in your web browser. As far as more benevolent applications are concerned, a quantum computer would be capable of molecular modeling that takes into account all interactions between the particles involved. This in turn would enable the development of highly efficient solar cells and new drugs. To have practical applications, a quantum computer needs to incorporate hundreds or even thousands of qubits. And that is where it gets tricky. As it turns out, the unstable nature of the connection between qubits remains the major obstacle preventing us from using quantum walks of particles for quantum computation. Unlike their classical analogs, quantum structures are extremely sensitive to external noise. To prevent a system of several qubits from losing the information stored in it, liquid nitrogen (or helium) needs to be used for cooling. Plenty of schemes have been proposed for the experimental realization of a separate qubit. In an earlier study, a research team led by Prof. Fedichkin demonstrated that a qubit could be physically implemented as a particle "taking a quantum walk" between two extremely small semiconductors known as quantum dots, which are connected by a "quantum tunnel." From the perspective of an electron, the quantum dots represent potential wells. Thus, the position of the electron can be used to encode the two basis states of the qubit--|0? and |1?--depending on whether the particle is in one well or the other. Rather than sit in one of the two wells, the electron is smeared out between the two different states, taking up a definite position only when its coordinates are measured. In other words, it is in a superposition of two states. If an entangled state is created between several qubits, their individual states can no longer be described separately from one another, and any valid description must refer to the state of the whole system. This means that a system of three qubits has a total of 8 basis states and is in a superposition of them: A|000?+B|001?+C|010?+D|100?+E|011?+F|101?+G|110?+H|111?. By influencing the system, one inevitably affects all of the 8 coefficients, whereas influencing a system of regular bits only affects their individual states. By implication, n bits can store n variables, while n qubits can store 2? variables. Qudits offer an even greater advantage, since n four-level qudits (aka ququarts) can encode 4?, or 2?×2? variables. To put this into perspective, 10 ququarts store approximately 100,000 times more information than 10 bits. With greater values of n, the zeros in this number start to pile up very quickly. In this study, Alexey Melnikov and Leonid Fedichkin obtain a system of two qudits implemented as two entangled electrons quantum-walking around the so-called cycle graph. To make one, the scientists had to "connect the dots" forming a circle (once again, these are quantum dots, and they are connected by the effect called quantum tunneling). The entanglement of the two electrons is caused by the mutual electrostatic repulsion experienced by like charges. It is possible to create a system of even more qudits in the same volume of semiconductor material. To do this, it is necessary to connect quantum dots in a pattern of winding paths and have more wandering electrons. The quantum walks approach to quantum computation is convenient because it is based on a natural process. Nevertheless, the presence of two identical electrons in the same structure was a source of additional difficulties that had remained unsolved. The phenomenon of particle entanglement plays a pivotal role in quantum information processing. However, in experiments with identical particles, it is necessary to distinguish so-called false entanglement, which can arise between electrons that are not interacting, from genuine entanglement. To do this, the scientists performed mathematical calculations for both cases, viz., with and without entanglement. They observed the changing distribution of probabilities for the cases with 6, 8, 10, and 12 dots, i.e., for a system of two qudits with three, four, five, and six levels each. The scientists demonstrated that their proposed system is characterized by a relatively high degree of stability. It has been a long time since people first set their hearts on building a universal quantum computer, but so far we have been unable to connect a sufficient number of qubits. The work of the Russian researchers brings us one step closer to a future where quantum computations are commonplace. And although there are algorithms that quantum computers could never accelerate, others would still benefit enormously from devices able to exploit the potential of large numbers of qubits (or qudits). These alone would be enough to save us a couple of thousand years. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


Ganbold G.,Institute of Physics and Technology
Physics of Particles and Nuclei | Year: 2012

We study the behavior of the QCD effective coupling α s in the low-energy region by exploiting the conventional meson spectrum within a relativistic quantum-field model based on analytical confinement of quarks and gluons. The spectra of quark-antiquark and two-gluon bound states are defined by using a master equation similar to the ladder Bethe-Salpeter equation. A new, independent and specific infrared-finite behavior of QCD coupling is found below energy scale ~1 GeV. Particularly, an infrared-fixed point is extracted at α s(0) ≅ 0. 757 for confinement scale Λ = 345 MeV. We provide a new analytic estimate of the lowest-state glueball mass. As applications, we also estimate masses of some intermediate and heavy mesons as well as the weak-decay constants of light mesons. By introducing only a minimal set of parameters (the quark masses m f and Λ) we obtain results in reasonable agreement with recent experimental data in a wide range of energy scale ~0. 1-10 GeV. We demonstrate that global properties of some low-energy phenomena may be explained reasonably in the framework of a simple relativistic quantum-field model if one guesses correct symmetry structure of the quark-gluon interaction in the confinement region and uses simple forms of propagators in the hadronisation regime. The model may serve a reasonable framework to describe simultaneously different sectors in low-energy particle physics. © 2012 Pleiades Publishing, Ltd.


Beisenkhanov N.B.,Institute of Physics and Technology
Technical Physics | Year: 2011

The composition and structure of homogeneous SiC1.4, SiC0.95, SiC0.7, SiC0.4, SiC0.12, and SiC0.03 layers obtained by multiple high-dose implantation of carbon ions with energies of 40, 20, 10, 5, and 3 keV into silicon are analyzed using Auger electron spectroscopy, X-ray diffraction, IR spectroscopy, and atomic force microscopy. The effect of decomposition of carbon and carbon-silicon clusters on the formation of Si-C tetrahedral bonds and on crystallization in silicon layers with high and low concentrations of carbon is considered. © 2011 Pleiades Publishing, Ltd.


Tynyshtykbaev K.B.,Institute of Physics and Technology
2011 International Conference on Multimedia Technology, ICMT 2011 | Year: 2011

Self-organization of highly ordered mosaic structure of porous Si at long anodic etching of p-Si (100) in electrolyte with internal source of the current is observed. Sizes of the nanocrystallites islets of porous Si, the period of their location and self-organization of the mosaic structure of porous silicon are defined by the effect of forces of elastically-deformation, defectdeformation and capillary-fluctuation that exist at the interface of electrolyte/porous Si/c-Si/ in process of pores formation. Process of spontaneous formation of mosaic structure por-Si has place in results from relaxation of the elastically-strained layer of porous surface and effect of capillary-fluctuation forces. Conditions of development of these forces depend on the self-coordinated parameters of etching of interface heterophase of electrochemical system the electrolyte/porous Si/c-Si/ and parameters of electrodes and electrochemical cell. © 2011 IEEE.


Ganbold G.,Institute of Physics and Technology
Journal of Physics: Conference Series | Year: 2011

A relativistic quantum-field model based on analytical confinement is developed to build stable bound states of spin-half and spin-one particles. The spectra of two-quark ground states are defined by using the ladder Bethe-Salpeter equation. An analytic expression for the running coupling in QCD is obtained that can be extended to the low energy region. By comparing the obtained result with recent experimental data on meson masses we obtain a new, independent and specific infrared-finite behavior of QCD coupling below energy scale ∼ 1 GeV. Particularly, an infrared-fixed point is extracted at αs(0) ≃ 0.757. We also calculate masses of some conventional mesons in the range of 0.8 - 9.5 GeV.


Rudenko K.,Institute of Physics and Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

This pdf file contains the Front Matter associated with SPIE Proceedings volume 7521, including Title page, Copyright information, Table of Contents, Conference Committee listing, and Introduction (if any). © 2010 Copyright SPIE - The International Society for Optical Engineering.


Beisenkhanov N.B.,Institute of Physics and Technology
Physics of the Solid State | Year: 2011

The influence of treatment in hydrogen and oxygen glow discharge plasmas on the structural and optical properties of 270- to 350-nm-thick SnOx films prepared using magnetron sputtering and the sol-gel method on the glass substrate has been considered. It has been demonstrated that the plasmas exert segregating and destroying effects on the structure of crystal grains, the transparency of films, and on their porosity. It has been established that treatment in the hydrogen glow discharge plasma makes it possible in principle to prepare crystal-amorphous nanostructures in which tin oxide nanocrystals of high quality alternate with tin oxide clusters. © 2011 Pleiades Publishing, Ltd.


Magner A.G.,Institute for Nuclear Research of Ukraine | Vlasenko A.A.,Institute for Nuclear Research of Ukraine | Vlasenko A.A.,Institute of Physics and Technology | Arita K.,Nagoya Institute of Technology
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2013

The trace formula for the density of single-particle levels in the two-dimensional radial power-law potentials, which nicely approximate up to a constant shift the radial dependence of the Woods-Saxon potential and its quantum spectra in a bound region, was derived by the improved stationary phase method. The specific analytical results are obtained for the powers α=4 and 6. The enhancement of periodic-orbit contribution to the level density near the bifurcations are found to be significant for the description of the fine shell structure. The semiclassical trace formulas for the shell corrections to the level density and the energy of many-fermion systems reproduce the quantum results with good accuracy through all the bifurcation (symmetry breaking) catastrophe points, where the standard stationary-phase method breaks down. Various limits (including the harmonic oscillator and the spherical billiard) are obtained from the same analytical trace formula. © 2013 American Physical Society.

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