Effective Eigenmode Description of Normal and Superfluid 4He
- 35 Downloads
- 1 Citations
Abstract
We determine the behavior of the phonon excitations in liquid 4He, covering both the normal and superfluid phase, for a range of temperatures T (1 < T < 4.2 K), wave numbers q (0.1 < q < 2.2 Å−1) and pressures p (0 < p < 25 bars), by means of a numerical fitting procedure based on the effective eigenmode description of the density correlation function. We find that the q, p and T dependence of all inelastic neutron scattering data can be well described by using only one adjustable parameter, the damping rate of the momentum fluctuations. We establish that there is a close similarity between classical liquids, normal-fluid 4He and superfluid 4He. We observe, for all q-values, a marked change in the damping rate of the momentum fluctuations as one passes through the superfluid-transition temperature Tλ. For the roton excitations, this results in a heavily damped (overdamped at p = 20 bars) mode in the normal phase, in contrast to the propagating mode observed in the superfluid phase. The change in damping rate is found to occur predominantly in a small temperature region just below Tλ, for all q-values. We do not find any evidence for the sudden appearance of the predicted “renormalized single-particle” excitations as one enters the superfluid phase. We argue that the full dispersion curve of the phonon-maxon-roton excitations can be understood for all temperatures and pressures in terms of the damping rate of the momentum fluctuations, whereas the rapid changes in this damping rate near Tλ can be viewed as a direct consequence of the Bose symmetry requirements on the 4He-wavefunction.
Keywords
Correlation Function Dispersion Curve Normal Phase Close Similarity Small TemperaturePreview
Unable to display preview. Download preview PDF.
REFERENCES
- 1.L. D. Landau, J. Phys. U.S.S.R 5, 71 (1941); 11, 91 (1947).Google Scholar
- 2.H. Palevsky, K. Otnes, K. E. Larsson, R. Pauli, and R. Stedman, Phys. Rev. 108, 1346 (1957); H. Palevsky, K. Otnes and K. E. Larsson, Phys. Rev. 112, 11 (1958).Google Scholar
- 3.L. Yarnell, G. P. Arnold, P. J. Bendt, and E. C. Kerr, Phys. Rev. Lett. 1, 9 (1958); Phys. Rev. 113, 1379 (1959).CrossRefGoogle Scholar
- 4.G. Henshaw, Phys. Rev. Lett. 1, 127 (1958).CrossRefGoogle Scholar
- 5.R. P. Feynman, in Progress in Low Temperature Physics, Vol. 1, C. J. Gorter (ed.), North-Holland, Amsterdam (1955).Google Scholar
- 6.F. London, Nature 141, 643 (1938).Google Scholar
- 7.V. F. Sears, E. C. Svensson, P. Martel, and A. D. B. Woods, Phys. Rev. Lett. 49, 279 (1982); E. C. Svensson, in Proceedings of the 1984 Workshop of High-Energy Excitations in Condensed Matter, Vol. II, Los Alamos National Laboratory Publication LA-10227-C, Los Alamos National Laboratory, Los Alamos (1984), p. 456, and references therein.CrossRefGoogle Scholar
- 8.P. E. Sokol, in Bose-Einstein Condensation, A. Griffin, D. W. Snoke, and S. Stringari (eds.), University Press, New York (1995), p. 51, and references therein.Google Scholar
- 9.D. M. Ceperley and E. L. Pollock, Phys. Rev. Lett. 56, 351 (1986).CrossRefPubMedGoogle Scholar
- 10.H. R. Glyde and A. Griffin, Phys. Rev. Lett. 65, 1454 (1990).CrossRefPubMedGoogle Scholar
- 11.W. Montfrooij, E. C. Svensson, and I. M. de Schepper, J. Low Temp. Phys. 89, 437 (1992).CrossRefGoogle Scholar
- 12.W. Montfrooij and E. C. Svensson, Physica B 194–196, 521 (1994).Google Scholar
- 13.E. C. Svensson, W. Montfrooij, and I. M. de Schepper, Phys. Rev. Lett. 77, 4398 (1996).CrossRefPubMedGoogle Scholar
- 14.E. G. D. Cohen and I. M. de Schepper, Il Nuovo Cimento 12D, 521 (1984), and references therein.Google Scholar
- 15.R. F. Zwanzig, in Lectures in Theoretical Physics, Vol. 3, Interscience, New York (1961), p. 106.Google Scholar
- 16.H. Mori, Prog. Theor. Phys. 33, 423 (1965).Google Scholar
- 17.W. E. Alley and B. J. Alder, Phys. Rev. A 27, 3158 (1983).CrossRefGoogle Scholar
- 18.E. G. D. Cohen, I. M. de Schepper, and M. J. Zuilhof, Physica B 127, 282 (1984); Phys. Lett. A 101, 399 (1984).Google Scholar
- 19.C. Bruin, J. P. J. Michels, J. C. van Rijs, L. A. de Graaf, and I. M. de Schepper, Phys. Lett. 110A, 40 (1985).Google Scholar
- 20.B. Kamgar-Parsi, E. G. D. Cohen, and I. M. de Schepper, Phys. Rev. A 35, 4781 (1987).CrossRefPubMedGoogle Scholar
- 21.I. M. de Schepper, E. G. D. Cohen, and B. Kamgar-Parsi, J. Stat. Phys. 54, 273 (1989).CrossRefGoogle Scholar
- 22.I. M. de Schepper, P. Verkerk, A. A. van Well, and L. A. de Graaf, Phys. Rev. Lett. 50, 974 (1983).CrossRefGoogle Scholar
- 23.I. M. de Schepper, P. Verkerk, A. A. van Well, and L. A. de Graaf, Phys. Lett. 104A, 29 (1984).Google Scholar
- 24.A. A. van Well, P. Verkerk, L. A. de Graaf, J.-B. Suck, and J. R. D. Copley, Phys. Rev. A 31, 3391 (1985).CrossRefPubMedGoogle Scholar
- 25.P. Verkerk, A. A. van Well, and I. M. de Schepper, J. Phys. C: Solid State Phys. 20, L979 (1987).CrossRefGoogle Scholar
- 26.A. A. van Well and L. A. de Graaf, Phys. Rev. A 32, 2396 (1985).CrossRefPubMedGoogle Scholar
- 27.P. A. Egelstaff, W. Glaser, D. Litchinsky, E. Schneider, and J.-B. Suck, Phys. Rev. A 27, 1106 (1983).CrossRefGoogle Scholar
- 28.W. Montfrooij, L. A. de Graaf, and I. M. de Schepper, Phys. Rev. A 44, 6559 (1991).CrossRefPubMedGoogle Scholar
- 29.W. Montfrooij, L. A. de Graaf, and I. M. de Schepper, Phys. Rev. B 45, 3111 (1992).CrossRefGoogle Scholar
- 30.I. M. de Schepper, J. C. van Rijs, A. A. van Well, P. Verkerk, and L. P. de Graaf, Phys. Rev. A 29, 1602 (1984).CrossRefGoogle Scholar
- 31.C. Bruin, J. C. van Rijs, L. A. de Graaf, and I. M. de Schepper, Phys. Rev. A 34, 3196 (1986).CrossRefPubMedGoogle Scholar
- 32.I. M. de Schepper, E. G. D. Cohen, C. Bruijn, J. C. van Rijs, W. Montfrooij, and L. A. de Graaf, Phys. Rev. A 38, 271 (1988).CrossRefPubMedGoogle Scholar
- 33.R. L. McGreevy and E. W. J. Mitchell, Phys. Rev. Lett. 55, 398 (1985).CrossRefPubMedGoogle Scholar
- 34.P. Westerhuijs, W. Montfrooij, L. A. de Graaf, and I. M. de Schepper, Phys Rev. A 45, 3749 (1992).CrossRefPubMedGoogle Scholar
- 35.E. C. Svensson, in Excitations in 2-Dimensional and 3-Dimensional Quantum Fluids, A. F. G. Wyatt and H. J. Lauter (eds.) Plenum Press, New York (1991), p. 59.Google Scholar
- 36.D. Forster, Hydrodynamic Fluctuations, Broken Symmetry, and Correlation Functions, W. A. Benjamin Inc., Reading, Massachusetts (1975).Google Scholar
- 37.A. D. B. Woods, E. C. Svensson, and P. Martel, Can. J. Phys. 56, 302 (1978).Google Scholar
- 38.A. Griffin, Excitation in a Bose-Condensed Liquid, Cambridge University Press, New York (1993).Google Scholar
- 39.R. M. Crevecoeur, R. Verberg, I. M. de Schepper, L. A. de Graaf, and W. Montfrooij, Phys. Rev. Lett. 74, 5052 (1995).CrossRefPubMedGoogle Scholar
- 40.P. C. Hohenberg and P. C. Martin, Annals of Phys. 34, 291 (1965).CrossRefGoogle Scholar
- 41.H. R. Glyde, Phys. Rev. B 45, 7321 (1992).CrossRefGoogle Scholar
- 42.G. A. Williams, Phys. Rev. Lett. 68, 2054 (1992).CrossRefPubMedGoogle Scholar
- 43.G. A. Williams, Phys. Rev. Lett. 71, 392 (1993).CrossRefPubMedGoogle Scholar
- 44.A. D. B. Woods, E. C. Svensson, and P. Martel, Phys. Lett. 57A, 439 (1976).Google Scholar
- 45.A. D. B. Woods, E. C. Svensson, and P. Martel, in Proceedings of the Conference on Neutron Scattering, R. M. Moon (ed.), Vol. 2, National Technical Information Service, Springfield (1976), p. 1010.Google Scholar
- 46.E. F. Talbot, H. R. Glyde, W. G. Stirling, and E. C. Svensson, Phys. Rev. B 38, 11229 (1988).CrossRefGoogle Scholar
- 47.A. D. B. Woods and E. C. Svensson, Phys. Rev. Lett. 41, 974 (1978).CrossRefGoogle Scholar
- 48.W. Montfrooij and E. C. Svensson, Czech. Phys. 46(S1), 259 (1996).Google Scholar
- 49.A. D. B. Woods and E. C. Svensson, unpublished work from the study reported in Ref. 47.Google Scholar
- 50.B. N. Brockhouse, in Inelastic Scattering of Neutrons in Solids and Liquids, IAEA, Vienna (1961), p. 113.Google Scholar
- 51.V. F. Sears, Nucl. Inst. and Meth. 123, 521 (1975).CrossRefGoogle Scholar
- 52.V. V. Sychev, A. A. Vasserman, A. D. Kozlov, G. A. Spiridinov, and V. P. Tsymarny, Thermodynamic Properties of Helium, Springer-Verlag, Berlin (1987).Google Scholar
- 53.R. M. Crevecoeur, H. E. Smorenburg, and I. M. de Schepper, J. Low Temp. Phys. 105, 149 (1996).CrossRefGoogle Scholar
- 54.E. C. Svensson, in Elementary Excitations in Quantum Fluids, K. Ohbayashi and M. Watabe (eds.), Springer-Veriag, Heidelberg (1989), p. 59.Google Scholar
- 55.H. van Beijeren and M. H. Ernst, Physica 68, 437 (1973).CrossRefGoogle Scholar
- 56.I. M. de Schepper, P. Verkerk, A. A. van Well, and L. A. de Graaf, Phys. Lett. 104A, 29 (1984).Google Scholar
- 57.E. G. D. Cohen, P. Westerhuijs, and I. M. de Schepper, Phys. Rev. Lett. 59, 2872 (1987).CrossRefPubMedGoogle Scholar
- 58.J. Maynard, Phys. Rev. B 14, 3868 (1976).CrossRefGoogle Scholar
- 59.O. W. Dietrich, E. H. Graf, C. H. Huang, and L. Passell, Phys. Rev. A 5, 1377 (1972).CrossRefGoogle Scholar
- 60.R. A. Cowley and A. D. B. Woods, Can. J. Phys. 49, 177 (1971).Google Scholar
- 61.C. H. Aldrich, III, C. J. Pethick, and D. Pines, J. Low Temp. Phys. 25, 691 (1976).CrossRefGoogle Scholar
- 62.F. Mezei and W. G. Stirling, in 75th Jubilee Conference on Helium-4, J. G. M. Armitage (ed.), World Scientific, Singapore (1983), p. 111.Google Scholar
- 63.L. D. Landau and I. M. Khalatnikov, Zh. Eksp. Teor. Fiz. 19, 637 (1949).Google Scholar
- 64.K. Ohbayashi in Excitations in 2-Dimensional and 3-Dimensional quantum, Fluids, A. F. G. Wyatt and H. J. Lauter (eds.), Plenum Press, New York (1991), p. 77.Google Scholar
- 65.K. J. Juge and A. Griffin, J. Low Temp. Phys. 97, 105 (1994).CrossRefGoogle Scholar
- 66.W. Montfrooij and I. M. de Schepper, Phys. Rev. B 51, 15607 (1995).CrossRefGoogle Scholar
- 67.see, e.g., J. J. van Loef and E. G. D. Cohen, Phys. Rev. B 39, 4715 (1989).CrossRefGoogle Scholar
- 68.R. M. Crevecoeur, H. E. Smorenburg, I. M. de Schepper, W. Montfrooij, and E. C. Svensson, Czech. Phys. 46(S1), 257 (1996).Google Scholar