On electric polarization of helium atoms by acceleration

Possibility of explanation of high electric activity in superfluid helium [1–3] by polarization of helium atoms caused by acceleration is researched. It is shown that this effect is insufficient to explain the phenomenon. Исследована возможность объяснения наблюдаемой повышенной электрической активн...

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Опубліковано в: :Вопросы атомной науки и техники
Дата:2012
Автори: Poluektov, Yu.M., Savchenko, V.N.
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Мова:English
Опубліковано: Національний науковий центр «Харківський фізико-технічний інститут» НАН України 2012
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Цитувати:On electric polarization of helium atoms by acceleration / Yu.M. Poluektov, V.N. Savchenko // Вопросы атомной науки и техники. — 2012. — № 1. — С. 299-301. — Бібліогр.: 6 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-107162
record_format dspace
spelling Poluektov, Yu.M.
Savchenko, V.N.
2016-10-14T10:40:31Z
2016-10-14T10:40:31Z
2012
On electric polarization of helium atoms by acceleration / Yu.M. Poluektov, V.N. Savchenko // Вопросы атомной науки и техники. — 2012. — № 1. — С. 299-301. — Бібліогр.: 6 назв. — англ.
1562-6016
PACS: 67.40.Pm
https://nasplib.isofts.kiev.ua/handle/123456789/107162
Possibility of explanation of high electric activity in superfluid helium [1–3] by polarization of helium atoms caused by acceleration is researched. It is shown that this effect is insufficient to explain the phenomenon.
Исследована возможность объяснения наблюдаемой повышенной электрической активности сверхтекучего гелия [1–3] эффектом поляризации атома гелия при его ускорении. Показано, что этой причины не достаточно для объяснения величины эффекта.
Досліджена можливість пояснення спостереженої підвищеної електричної активності надплинного гелію [1–3] ефектом поляризації атома гелію при його прискоренні. Показано, що цієї причини недостатньо для пояснення величини ефекту.
en
Національний науковий центр «Харківський фізико-технічний інститут» НАН України
Вопросы атомной науки и техники
Section E. Phase Transitions and Diffusion Processes in Condensed Matter and Gases
On electric polarization of helium atoms by acceleration
Об электрической поляризации атомов гелия при ускорении
Об електричній поляризації атомів гелію при прискоренні
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title On electric polarization of helium atoms by acceleration
spellingShingle On electric polarization of helium atoms by acceleration
Poluektov, Yu.M.
Savchenko, V.N.
Section E. Phase Transitions and Diffusion Processes in Condensed Matter and Gases
title_short On electric polarization of helium atoms by acceleration
title_full On electric polarization of helium atoms by acceleration
title_fullStr On electric polarization of helium atoms by acceleration
title_full_unstemmed On electric polarization of helium atoms by acceleration
title_sort on electric polarization of helium atoms by acceleration
author Poluektov, Yu.M.
Savchenko, V.N.
author_facet Poluektov, Yu.M.
Savchenko, V.N.
topic Section E. Phase Transitions and Diffusion Processes in Condensed Matter and Gases
topic_facet Section E. Phase Transitions and Diffusion Processes in Condensed Matter and Gases
publishDate 2012
language English
container_title Вопросы атомной науки и техники
publisher Національний науковий центр «Харківський фізико-технічний інститут» НАН України
format Article
title_alt Об электрической поляризации атомов гелия при ускорении
Об електричній поляризації атомів гелію при прискоренні
description Possibility of explanation of high electric activity in superfluid helium [1–3] by polarization of helium atoms caused by acceleration is researched. It is shown that this effect is insufficient to explain the phenomenon. Исследована возможность объяснения наблюдаемой повышенной электрической активности сверхтекучего гелия [1–3] эффектом поляризации атома гелия при его ускорении. Показано, что этой причины не достаточно для объяснения величины эффекта. Досліджена можливість пояснення спостереженої підвищеної електричної активності надплинного гелію [1–3] ефектом поляризації атома гелію при його прискоренні. Показано, що цієї причини недостатньо для пояснення величини ефекту.
issn 1562-6016
url https://nasplib.isofts.kiev.ua/handle/123456789/107162
citation_txt On electric polarization of helium atoms by acceleration / Yu.M. Poluektov, V.N. Savchenko // Вопросы атомной науки и техники. — 2012. — № 1. — С. 299-301. — Бібліогр.: 6 назв. — англ.
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AT savchenkovn obélektričeskoipolârizaciiatomovgeliâpriuskorenii
AT poluektovyum obelektričníipolârizacííatomívgelíûpripriskorenní
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first_indexed 2025-11-26T00:08:21Z
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fulltext ON ELECTRIC POLARIZATION OF HELIUM ATOMS BY ACCELERATION Yu.M. Poluektov 1∗and V.N. Savchenko 2 1National Science Center “Kharkov Institute of Physics and Technology”, 61108, Kharkov, Ukraine 2V.N. Karazin Kharkov National University, 61077, Kharkov, Ukraine (Received October 31, 2011) Possibility of explanation of high electric activity in superfluid helium [1–3] by polarization of helium atoms caused by acceleration is researched. It is shown that this effect is insufficient to explain the phenomenon. PACS: 67.40.Pm 1. INTRODUCTION In a number of experimental works [1–3] an unex- pected high electric activity of superfluid helium was observed, existing under different conditions. In work [1] it was discovered that propagation of second sound waves is followed by oscillations of electric field. In subsequent experiments [2, 3] it was shown that the polarization in helium can arise without temperature oscillations if continuous fluxes are present. In order to explain experiments [1–3], studying electric phe- nomena in superfluid helium, in [4, 5] a mechanism of polarization of helium atoms under the action of gravitation and acceleration was proposed. It was shown [4, 5], based on analogy with Stuart-Tolmen effect and some phenomenological arguments, that accelerated atom must gain dipole moment �d = γ�̇v, (1) where �̇v is the acceleration of atom, γ = Mκ0/2Z|e| is the “gravitoelectric” susceptibility, κ0 is the polar- izability of single atom, M,Z are the atomic mass and nucleus charge, |e| is the elementary charge. Gravitational and inertia forces are sensitive nei- ther to magnitude, nor to the sign of the charge, thus the nature of the predicted in [4,5] effect needs more detailed analysis. In connection with this a quantum- mechanical problem of helium atom in the ground state under the action of external forces is considered in this work. It is shown, that if these forces are of gravitational and inertial nature, atom is not polar- ized. Accelerated atom in gravitational field can be- come polarized if there are also forces of other nature acting upon it. The obtained value of polarization is three orders of magnitude less than the estimated in works [4, 5] and is of different sign. 2. CONSIDERATIONS Consider hamiltonian of helium atom in ground state with a constant force �F acting upon its nucleus and �f acting upon its electrons: H = − h̄2 2M0 ��R − h̄2 2m ��r1 − h̄2 2m ��r2− −Ze2/|�R− �r1| − Ze2/|�R− �r2|+ +e2/|�r1 − �r2| − �F �R− �f�r1 − �f�r2, (2) where �R denotes coordinate of nucleus, �r1, �r2 are co- ordinates of electrons, M0,m are masses of nucleus and electron respectively. The next coordinate trans- formation: �x1 = �r1 − �R, �x2 = �r2 − �R, �X = (M0 �R+m�r1 +m�r1)/(M0 + 2m), (3) reduces the problem to that of helium atom in effec- tive electrical field with intensity of �Eeff = (m�F −M0 �f)/(|e|M). (4) Full wave function of helium atom can be presented in the next form Φ( �X, �x1, �x1) = ϕ( �X)Ψ(�x1, �x1), (5) where ϕ( �X) is the wave function of whole atom motion and is not responsible for its polariza- tion. Variational approach is used for calculations. For helium atom in ground state approximately Ψ(�x1, �x1) = ψ(�x1)ψ(�x1), where probe function is ψ(�r) = C(ψ0(�r) +Bψ1(�r)), (6) ∗Corresponding author E-mail address: yuripoluektov@kipt.kharkov.ua PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY, 2012, N 1. Series: Nuclear Physics Investigations (57), p. 299-301. 299 C = (1 +B)1/2 is a normalization constant, ψ0(�r) = √ Z3∗ πa3 0 exp(−Z∗ r a0 ), ψ1(�r) = √ Z5∗ πa5 0 r cosϑ exp(−Z∗ r a0 ), (7) a0 = h̄2/me2 denotes Bohr radius, ϑ is the angle be- tween the electric field and radius-vector of electron. Wave function contains two variational parameters Z∗ and B. Accuracy of calculation with this wave function is about 10%. In the first order of magnitude by small ratio of external field to field, created by elementary charge at distance of Bohr radius, the equation for dipole moment is �d = κ�Eeff , (8) where in used estimation κ = 8a3 0/AZ 3 1 , A = 31/16, Z1 = 27/16. Consider helium atom in gravity field �g and uniform electric field �E. In addition, consider a force of another nature �Fe acting upon atomic nu- cleus and a force �fe acting upon electrons. We do not specify the nature of these forces yet. Then the resultant force acting upon nucleus is �F = M0�g + Z|e| �E + �Fe, and resultant force acting upon electrons is �f = M0�g − |e| �E + �fe. Taking (4) into account, effective intensity becomes �Eeff = �E + (m�Fe −M0 �fe)/(|e|M). (9) There is no term containing gravity in this equation. Thus, in absence of electric field and forces of an- other nature, �Eeff = 0, the atom can not be polar- ized. For forces resulting in polarization the next condition must be satisfied m�Fe −M0 �fe �= 0. (10) For gravitational forces this condition is not satis- fied, so gravity itself can not lead to polarization. It is natural, because under the action of gravity nu- cleus and electrons move with the same acceleration and no charge separation occurs. Inertial force −M�̇v is also proportional to the mass, and therefore, as in the case of gravity, can not itself result in polarization of atom. Resultant force acting upon atom �Fa = M�g + �Fe + Z �fe, (11) is the sum of gravitational force and forces of other nature. Under act of this force atom in non- relativistic approximation moves with acceleration �̇v = �Fa/M . Consider separately two cases. The first, when the force of another nature acting upon electron is zero: �fe = 0. Also assume the absence of electric field �E = 0. Taking into account (8) and (9) the di- pole moment of a single atom is �d = κm |e| (�̇v − �g). (12) If the force �Fe is so that atom is not accelerated �̇v = 0, then from (12) can be concluded that direction of di- pole moment of atom is opposite to the direction of gravitational field. It is simple, because the position of nucleus is fixed by the force of another nature, �Fe, and electrons, that are assumed not to experience an- other nature force, shift in the direction of gravity. If there is no gravity, atom moves with acceleration �̇v under the action of force �Fe, and dipole moment has the same direction as acceleration. Electron, that ex- periences coulomb force of the nucleus, lags from ac- celerated nucleus. Then the force �Fe must be under- stood as force acting upon nucleus from accelerated lattice. Now consider �Fe = 0 and force �fe acting upon electrons. It is not clear how the case, when there is a force that fixes the position of electron cloud and does not affect the nucleus, can be implemented. Most likely, this is just a hypothetical possibility. In this case the mass of nucleus, instead of electron mass, enters the numerator of the equation for dipole mo- ment, and its sign changes to the opposite: �d = −κM0 Z|e| (�̇v − �g). (13) Note that in this form (1) the dipole moment, in- duced by polarization and acceleration, is presented in works [4, 5]. Consider polarization of solid dielectric, that con- tains n atoms in unit volume and is accelerated under the action of external force �Fe = M�̇v. The coulomb force, that acts on electron from its nucleus, was taken into account in the derivation of formula for effective intensity (9). Atoms in the accelerated di- electric are polarized under the action of effective field. It means, that electric field �E appears acting upon electrons of every atom. For displacement vec- tor �D = �E + 4π �P in absence of external charges and currents the equations div �D = 0 and ∂ �D/∂t = 0 are true. Thus, in assumption of no spontaneous symme- try breakdown, �E = −4π �P , where polarization den- sity �P = n�d. Consider forces of another nature acting upon electron �fe = 0. Taking into account the last equations and (8), one finds �P = κnm ε|e| �̇v = γ�̇v, (14) where ε = 1 + 4πκn is the dielectric permittivity and γ = κnm/ε|e| is the gravitoelectric susceptibility. In our case this coefficient significantly differs from (1) presented in [4, 5] because there is the electron mass in the numerator instead of the atom mass. It means, that the effect is three orders of magnitude less than that given in works [4, 5]. Besides, equation (14) differs in sign from the corresponding equation in works [4, 5]. Estimated value of acceleration necessary for gaining dipole moment of polar molecule, that is about one debye, is �̇v = 0.5· 1024 cm/s2. Due to some estimations (private communication from A.S. 300 Rybalko) atom in superfluid helium can have sta- tic dipole moment about d ≈ 10−4D. Such value is reached at acceleration �̇v = 1020 cm/s2. Amplitude of acceleration in first sound wave is a = ωu(Δρ/ρ0), where u denotes sound velocity, ω is the frequency, Δρ/ρ0 is the ratio of density oscillation amplitude to equilibrium density. At sound velocity u ≈ 2.8· 104 cm/s and wavelength λ ≈ 10−1 cm the frequency is ω ≈ 1.8· 106 s−1. For typical value Δρ/ρ0 = 10−5 the amplitude of acceleration in sound wave is a = 5· 105 cm/s2. This value is three or- ders of magnitude less than necessary for obtaining needed dipole moment. At such acceleration and atomic density n ≈ 10−22 cm−3 an electric field E = 4πnd ≈ 10−13 CGSE units arises in dielectric. At wavelength λ ≈ 10−1 cm the appropriate poten- tial difference is U ≈ 10−12 V, that is three orders of magnitude less, than observed in work [1]. 3. CONCLUSIONS The research made in the present work allows to con- clude the following: • Neither gravitational nor inertial forces can lead to the polarization of atom, since they are not sensitive to the sign and magnitude of charge, and the acceleration under the action of these forces do not depend on the particle mass. Ac- tion of forces of another nature is necessary to respond for the polarization of atom. • Estimation of polarization of an accelerated solid dielectric, obtained in this work, is three orders of magnitude less than given in works [4,5]. • Considered effect in normal fluids must be even less than in solid dielectrics because of absence of long-range correlations. • There is a specific long-range order in superflu- ids, connected with the phase symmetry break- down, but apparently it cannot significantly in- crease the considered effect. Thus, estimations and considerations given in this paper allow us to conclude that observed electric activity of superfluid cannot be explained by the effect of polarization of helium due to acceleration. References 1. A.S. Rybalko. Observation of electrical induction in a wave of the second sound in He II // Fiz. Nizk. Temp. 2004, v. 30, p. 1321-1325. 2. A.S. Rybalko and S.P. Rubets. Observation of the mechanoelectric effect in He II // Fiz. Nizk. Temp. 2005, v. 31, p. 820-825. 3. A.S. Rybalko, S.P. Rubets, E.Ya. Rudavskii, V.A. Tikhiy, S.I. Tarapov, R.V. Golovashchen- ko, and V.N. Derkach. Microwave experiments in He II. New features of undamped superfluid flows // Fiz. Nizk. Temp. 2008, v. 34, p. 631-639. 4. L.A. Melnikovsky. Polarization of Dielectrics by Acceleration // arXiv :cond-mat/0505102v3 [cond-mat.soft], 2 Feb. 2008. 5. L.A. Melnikovsky. Polarization of Dielectrics by Acceleration // J. Low Temp. Phys. 2007, v. 148, p. 559-564. 6. L.D. Landau, E.M. Lifshitz. 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