Role of exchange interaction of identical particles of the discrete spectrum at simultaneous their tunneling through the potentia barrier dividing these particles

Work is devoted to theoretical research of influence of exchange interaction of identical particles on processes of simultaneous their tunneling through a rectangular potential barrier. Expression for exchange integral has been received and the analysis of dependence on parameters of identical parti...

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Datum:2009
Hauptverfasser: Martseniuk, L.S., Maydanyuk, S.P., Olhovsky, V.S.
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Sprache:English
Veröffentlicht: Національний науковий центр «Харківський фізико-технічний інститут» НАН України 2009
Schriftenreihe:Вопросы атомной науки и техники
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Zitieren:Role of exchange interaction of identical particles of the discrete spectrum at simultaneous their tunneling through the potentia barrier dividing these particles / L.S. Martseniuk, S.P. Maydanyuk, V.S. Olhovsky // Вопросы атомной науки и техники. — 2009. — № 3. — С. 51-53. — Бібліогр.: 4 назв. — англ.

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spelling irk-123456789-1112742017-01-10T03:02:20Z Role of exchange interaction of identical particles of the discrete spectrum at simultaneous their tunneling through the potentia barrier dividing these particles Martseniuk, L.S. Maydanyuk, S.P. Olhovsky, V.S. Ядерная физика и элементарные частицы Work is devoted to theoretical research of influence of exchange interaction of identical particles on processes of simultaneous their tunneling through a rectangular potential barrier. Expression for exchange integral has been received and the analysis of dependence on parameters of identical particles and characteristics of a quantum barrier is lead. It is shown, that as including of exchange energy changes phase characteristics of the wave functions describing process of tunneling, exchange processes influence on the time characteristics of tunneling. Робота присвячена теоретичному дослідженню впливу обмінної взаємодії тотожних часток на процеси одночасного туннелювання їх через прямокутний потенційний бар'єр. Був отриманий вираз для обмінного інтеграла V й проведений аналіз залежності V від параметрів тотожних часток і характеристик квантового бар'єра. Показано, що, оскільки включення обмінної енергії змінює фазові характеристики хвильових функцій, що описують процес туннелювання, то обмінні процеси впливають на часові характеристики туннелювання. Работа посвящена теоретическому исследованию влияния обменного взаимодействия тождественных частиц на процессы одновременного туннелирования их через прямоугольный потенциальный барьер. Было получено выражение для обменного интеграла V и проведен анализ зависимости V от параметров тождественных частиц и характеристик квантового барьера. Показано, что, поскольку включение обменной энергии изменяет фазовые характеристики волновых функций, описывающих процесс туннелирования, то обменные процессы влияют на временные характеристики туннелирования. 2009 Article Role of exchange interaction of identical particles of the discrete spectrum at simultaneous their tunneling through the potentia barrier dividing these particles / L.S. Martseniuk, S.P. Maydanyuk, V.S. Olhovsky // Вопросы атомной науки и техники. — 2009. — № 3. — С. 51-53. — Бібліогр.: 4 назв. — англ. 1562-6016 PACS: 03.65.-w, 03.65.Xp, 03.65.Nk http://dspace.nbuv.gov.ua/handle/123456789/111274 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
language English
topic Ядерная физика и элементарные частицы
Ядерная физика и элементарные частицы
spellingShingle Ядерная физика и элементарные частицы
Ядерная физика и элементарные частицы
Martseniuk, L.S.
Maydanyuk, S.P.
Olhovsky, V.S.
Role of exchange interaction of identical particles of the discrete spectrum at simultaneous their tunneling through the potentia barrier dividing these particles
Вопросы атомной науки и техники
description Work is devoted to theoretical research of influence of exchange interaction of identical particles on processes of simultaneous their tunneling through a rectangular potential barrier. Expression for exchange integral has been received and the analysis of dependence on parameters of identical particles and characteristics of a quantum barrier is lead. It is shown, that as including of exchange energy changes phase characteristics of the wave functions describing process of tunneling, exchange processes influence on the time characteristics of tunneling.
format Article
author Martseniuk, L.S.
Maydanyuk, S.P.
Olhovsky, V.S.
author_facet Martseniuk, L.S.
Maydanyuk, S.P.
Olhovsky, V.S.
author_sort Martseniuk, L.S.
title Role of exchange interaction of identical particles of the discrete spectrum at simultaneous their tunneling through the potentia barrier dividing these particles
title_short Role of exchange interaction of identical particles of the discrete spectrum at simultaneous their tunneling through the potentia barrier dividing these particles
title_full Role of exchange interaction of identical particles of the discrete spectrum at simultaneous their tunneling through the potentia barrier dividing these particles
title_fullStr Role of exchange interaction of identical particles of the discrete spectrum at simultaneous their tunneling through the potentia barrier dividing these particles
title_full_unstemmed Role of exchange interaction of identical particles of the discrete spectrum at simultaneous their tunneling through the potentia barrier dividing these particles
title_sort role of exchange interaction of identical particles of the discrete spectrum at simultaneous their tunneling through the potentia barrier dividing these particles
publisher Національний науковий центр «Харківський фізико-технічний інститут» НАН України
publishDate 2009
topic_facet Ядерная физика и элементарные частицы
url http://dspace.nbuv.gov.ua/handle/123456789/111274
citation_txt Role of exchange interaction of identical particles of the discrete spectrum at simultaneous their tunneling through the potentia barrier dividing these particles / L.S. Martseniuk, S.P. Maydanyuk, V.S. Olhovsky // Вопросы атомной науки и техники. — 2009. — № 3. — С. 51-53. — Бібліогр.: 4 назв. — англ.
series Вопросы атомной науки и техники
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fulltext ROLE OF EXCHANGE INTERACTION OF IDENTICAL PARTICLES OF THE DISCRETE SPECTRUM AT SIMULTANEOUS THEIR TUNNELING THROUGH THE POTENTIA BARRIER DIVIDING THESE PARTICLES L.S. Martseniuk∗, S.P. Maydanyuk†, V.S. Olhovsky Institute for Nuclear Research, National Academy of Sciences of Ukraine, 03680, Kiev, Ukraine (Received March 19, 2009) Work is devoted to theoretical research of influence of exchange interaction of identical particles on processes of simultaneous their tunneling through a rectangular potential barrier. Expression for exchange integral has been received and the analysis of dependence on parameters of identical particles and characteristics of a quantum barrier is lead. It is shown, that as including of exchange energy changes phase characteristics of the wave functions describing process of tunneling, exchange processes influence on the time characteristics of tunneling. PACS: 03.65.-w, 03.65.Xp, 03.65.Nk 1. INTRODUCTION As is known [1, 2], processes of interaction between quantum objects in some cases can be approximated precisely enough, having presented potential of inter- action as a rectangular quantum barrier that allows to simplify mathematical calculations considerably. Such approximation has allowed solving a num- ber of the important problems of quantum mechanics, and also welling to describe behavior of some quan- tum objects [2]. Therefore attractive is the use of it and for the decision of other tasks which yet it is not enough investigated. To the number questions which to the present tense in general was not explored, a question on influ- ence of exchange interaction on the processes of par- ticles tunneling in the field of rectangular potential barrier belongs to theoretical development of which the present work is devoted. 2. PASSAGE OF PARTICLES THROUGH A RECTANGULAR QUANTUM BARRIER: THE GENERAL CONSIDERATION In the beginning, let us consider a variant when on a rectangular potential barrier in width 2a and height U particles with a pulse p from left to right fall. Equa- tion of Schrödinger for particles looks like: HΨ(x, t) = − p2 2m ∆Ψ + UΨ = EΨ , or ∆Ψ + 2m h̄2 [E − U ] = 0. Time dependence of own functions is described by expression: ∆Ψ + 2m h̄2 [E − U ] = 0. Therefore for various areas decisions can be functions: ΨT = AT (x) exp ip1r/h̄ (1) at r > a, Ψ = B exp p2r/h̄ + C exp−p2r/h̄ (2) at r ∈ [−a, a], Ψ = D exp ip1r/h̄ + E exp−ip1r/h̄ (3) at r < −a, where p1 = √ 2mE, p2 = √ 2m (U − E). (4) Into a barrier to one particle correlations take place [2]: B = A 2 { 1 + ip1 p2 } exp [ (ip1 − p2) 2a h̄ ] , (5) C = A 2 { 1− ip1 p2 } exp [ (ip1 + p2) 2a h̄ ] . (6) Provided that these functions and their first deriva- tives are continuous on border of a barrier, it is possi- ble to get the exact decision of a task which is resulted in [1, 2] and other the sources. ∗Corresponding author E-mail address: prolisok77@yandex.ru †E-mail address: maidan@kinr.kiev.ua PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY, 2009, N3. . Series: Nuclear Physics Investigations (51), p.51-53 51 3. EXCHANGE INTERACTION OF IDENTICAL PARTICLES IN A FIELD OF A RECTANGULAR QUANTUM BARRIER Processes of collision are considered in system of the center of weights, for which speed of two particles before collision and after are opposite. Interaction of particles takes place in the field of a rectangular po- tential barrier (see figure). Let us consider two cases. The 1-st case: let us assume that the barrier is opaque to tunneling. In this case At in a formula (1) equals a zero. We will assume that a barrier becomes opaque to tunneling at some value of potential corresponding U ′. We have: Ψb,c = Ψb(r1)Ψc(r2), where Ψb(r1) is a solution of equation of: HΨb(r1) = EbΨb(r1), answering a value Eb, and, similarly, for Ψc(r2), corresponding to a value Ec. Energy of the system: E0 = Ec + Eb. Be- cause at a change placed of particles nothing changes, Ψc,b = Ψb(r2)Ψc(r1) will correspond to the same en- ergy E0, i.e. we have double degeneration of power level of the system. -a a R 0 r1 r2 cb ∆U U U‘ The circuit of interaction of two identical particles in a field of rectangular potential barrier The 2-nd case: a barrier is transparent for tunnel- ing. This case is realized, when the additional con- stant field is enclosed to area of a barrier in opposite to first direction, creating additional potential |∆U |. Then the size of potential of barrier will fall down on a size |∆U |, and have: U = U ′ − |∆U |. Let us consider additional potential |∆U | as small indignation in system of two particles, originally be- tween itself not interactive because of opacity of a barrier (a case 1). The additional probability of particles to pass through a barrier leads to removal of degeneration. At simultaneous approaching of particles b and c to the borders of a barrier there can be the ef- fects connected to exchange interaction of particles. Such effects will take place only for identical particles and their size is determined by “overlapping” of wave functions, i.e. they are realized when wave functions of particles will be distinct from zero in the same area of space. Taking to account that at interaction of identi- cal particles symmetric or antisymmetric states are realized only [1, 2], we shall have for symmetric or antisymmetric wave function of expression: Ψ1,2 = Ψ± = 1√ 2 (Ψ1 ±Ψ2) = = 1√ 2 [Ψb(r1)Ψc(r2)±Ψc(r1)Ψb(r2)] , (7) Size |Ψ±|2 - expresses probability of finding of the system in the symmetric or antisymmetric state de- pending on what particles are bosons or fermions. If particles were not identical, the system would be described a non symmetric function and we would have: |Ψ1,2|2 = |Ψb(r1)Ψc(r2)|2. For identical particles there is an additional element: |Ψb(r1)Ψc(r2)|∗Ψc(r1)Ψb(r2), and, consequently, ad- ditional energy, proper to energy of interaction of identical particles, appears. This energy, taking to account that a potential barrier has a form, indicated on figure, it is possible to calculate, in accordance with [1] on a formula: V = |∆U | ∫ r Ψ∗b(r1)Ψ∗c(r2)Ψb(r2)Ψc(r1). (8) From equalization (2) evidently, that a size V is determined by “overlapping” the wave functions Ψb and Ψc. For values r < −a and r > a the value of inte- gral is identically equally to zero, because for these areas U = 0, therefore will conduct integration for −a ≤ r ≤ a. Into a barrier for one particle the ratio (2), (5) and (6) are fair. At p2a/h̄ À 1 (i.e. provided that parameters an exhibitor strongly change from one border of a barrier to another) C À B [2]. Then it is possible to do such approaching: Ψ∗b(r1) = C∗ exp( p2r1 h̄ ) , Ψ∗c(r2) = C∗ exp(−p2r2 h̄ ) , Ψb(r2) = B exp( p2r2 h̄ ) + C exp(−p2r2 h̄ ) , Ψc(r1) = B exp(−p2r1 h̄ ) + C exp( p2r1 h̄ ) . In accordance with (8) have: 52 V = |∆U | ∫ ∫ C∗ exp p2r1 h̄ · C∗ exp−p2r1 h̄ · { B∗ exp p2r1 h̄ + C∗ exp−p2r1 h̄ } × × { B exp−p2r1 h̄ + C exp p2r1 h̄ } dr1 dr2 = |∆U | · {[ aBC∗ ]2 − [ CC∗ h̄ 2 p2 exp−2p2a h̄ ]2 } . (9) From (9) follows, that V = 0 at |B| = ∣∣∣ Ch̄ 2p2a exp−2p2a h̄ ∣∣∣, i.e. exchange interaction at such parameters of tun- neling is absent. More exact values it is possible to get for the proper parameters of tunneling, if to present the wave function of a moving particle as a wave package [3]. During [3] time of tunneling it is determined as: τPh T = h̄ ∂ arg AT ∂E . (10) As to exchange energy V there corresponds a certain value ω′ (V = h̄ω′) and, accordingly, ΨT passes in Ψ′T = A′T exp( i h̄ √ 2m(E ± V ) that, hence, is received also change of value of time of tunneling. 4. CONCLUSION Within the framework of approximation of poten- tial of interaction of particles as a rectangular poten- tial barrier expression for exchange integral of identi- cal particles, simultaneously tunneling through a bar- rier towards each other is found. It is shown, that the account of exchange in- teraction changes time of tunneling. Such analysis of processes of simultaneous tunneling is conducted first. References 1. L.D. Landau and E.M. Lifshitz. Quantum me- chanics, course of Theoretical Physics. Vol. 3. Moskva: ”Nauka” 1989, p. 768 (in Russian; Eng- lish variant: Oxford, Uk, Pergamon, 1982). 2. D. Bohm. Quantum theory. Moskva: ”Science”, 1965, 727p. (in Russian) 3. G. Privitera, G. Salesi, V.S. Olkhovsky, E. Re- cami. Tunneling times: An elementary introduc- tion // Rivista del Nuovo Cimento. 1991, v.26(4), p.55. 4. V.G. Levich, J.A. Vdovin, V.A. Miamlin. Course of theoretical physics. Vol.2. Moskva: ”Science”, 1971, p. 936 (in Russian). РОЛЬ ОБМЕННОГО ВЗАИМОДЕЙСТВИЯ ТОЖДЕСТВЕННЫХ ЧАСТИЦ ДИСКРЕТНОГО СПЕКТРА ПРИ ОДНОВРЕМЕННОМ ТУННЕЛИРОВАНИИ ИХ ЧЕРЕЗ ПОТЕНЦИАЛЬНЫЙ БАРЬЕР, РАЗДЕЛЯЮЩИЙ ЭТИ ЧАСТИЦЫ Л.С. Марценюк, С.П. Майданюк, В.С. Ольховский Работа посвящена теоретическому исследованию влияния обменного взаимодействия тождествен- ных частиц на процессы одновременного туннелирования их через прямоугольный потенциальный барьер. Было получено выражение для обменного интеграла V и проведен анализ зависимости V от параметров тождественных частиц и характеристик квантового барьера. Показано, что, поскольку включение обменной энергии изменяет фазовые характеристики волновых функций, описывающих процесс туннелирования, то обменные процессы влияют на временные характеристики туннелирова- ния. РОЛЬ ОБМIННОЇ ВЗАЄМОДIЇ ТОТОЖНИХ ЧАСТОК ДИСКРЕТНОГО СПЕКТРА ПРИ ОДНОЧАСНОМУ ТУННЕЛЮВАННI ЇХ ЧЕРЕЗ ПОТЕНЦIЙНИЙ БАР’ЄР, ЩО РОЗДIЛЯЄ ЦI ЧАСТИНКИ Л.С. Марценюк, С.П. Майданюк, В.С. Ольховський Робота присвячена теоретичному дослiдженню впливу обмiнної взаємодiї тотожних часток на про- цеси одночасного туннелювання їх через прямокутний потенцiйний бар’єр. Був отриманий вираз для обмiнного iнтеграла V й проведений аналiз залежностi V вiд параметрiв тотожних часток i характе- ристик квантового бар’єра. Показано, що, оскiльки включення обмiнної енергiї змiнює фазовi харак- теристики хвильових функцiй, що описують процес туннелювання, то обмiннi процеси впливають на часовi характеристики туннелювання. 53