Large-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>q</mml:mi></mml:math>neutron inclusive-scattering data from liquid<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi mathvariant="normal">He</mml:mi></mml:math>

Rinat, A.S.; Taragin, M. F.; Mazzanti, F.; Polls, A.

doi:10.1103/physrevb.57.5347

Cited by 17 publications

(22 citation statements)

References 32 publications

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“…To obtain the correct values of R 3 ϭ␤ 3 ϭā 3 /Q and R 4 ϭ␤ 4 ϭā 4 /(Q) 2 requires that the correct values of ā 3 and ā 4 emerge from the fit. We find ā 3 /ϭ2.5Ϯ0.2 Å Ϫ4 from our fit compared with a value ā 3 /ϭ5.1Ϯ0.5 Å Ϫ4 calculated using PIMC methods 39 and a value ā 3 /ϭ5.55 Å Ϫ4 calculated by Rinat et al 48 The coefficient ā 3 is somewhat below the expected value. In the fit, there is some compensation between ␤ 3 and ␤ 5 .…”

Section: Discussionsupporting

confidence: 49%

Condensate, momentum distribution, and final-state effects in liquid4He

2000

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We present benchmark, high precision measurements of the dynamic structure factor J(Q,y) of liquid 4 He at several temperatures over a wide wave vector transfer range 15рQр29 Å Ϫ1 . J(Q,y) is very different in the superfluid phase below T and in the normal phase above T where T ϭ2.17 K. Below T , J(Q,y) contains a pronounced additional contribution near yϭ0 that is asymmetric about yϭ0, reflecting a condensate contribution modified by asymmetric final-state ͑FS͒ effects. The asymmetry in J(Q,y) is direct qualitative evidence of a condensate. We analyze the data at all T using the same model of J(Q,y) consisting of a condensate fraction n 0 , a momentum distribution n*(k) for states kϾ0 above the condensate, and a FS broadening function R(Q,y). We find a condensate fraction given by n 0 (T)ϭn 0 (0)͓1Ϫ(T/T ) ␥ ͔ with n 0 (0)ϭ(7.25Ϯ0.75)% and ␥ϭ5.5Ϯ1.0 for TϽT , which is 30% below existing observed values, and n 0 ϭ(0Ϯ0.3)% for TϾT . We determine n(k) in both phases. The n*(k) is significantly narrower than a Gaussian in both superfluid and normal 4 He and narrowest in the normal phase. The final-state function is determined from the data and is the same within precision above and below T . The precise form of R(Q,y) is important in determining the value of n 0 (T) below T . When independent, theoretical R(Q,y) are used in the analysis, the n 0 (T) is found to be the same as or smaller than the above value.where បk is the 4 He atom momentum in the fluid, n(k) is the momentum distribution, and ប R ϭប 2 Q 2 /2m and v R ϭបQ/m are the free 4 He atom recoil energy and velocity, respectively. S IA (Q,) depends solely on n(k).At finite Q, interactions of the recoiling atom with its neighbors, denoted final-state ͑FS͒ effects, contribute to S(Q,). The observed S(Q,) is then 21,6,7

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Section: Discussionsupporting

confidence: 49%

Condensate, momentum distribution, and final-state effects in liquid4He

2000

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“…with the GRS series, cut at n = 2, as in Ref. 11. We now report what apparently are the first results for the next-to-leading order TC corrections and which are contained iñ…”

Section: Dominant Fsi Parts In the Response For Smooth And Singulmentioning

confidence: 68%

“…is the off-shell, eikonal phase in the coordinate representation, pertinent to the characteristic difference of interactions acting on '1' in (11). In order to obtain the appropriate on-shell phase one needs to replace the integration limits in (11) from 0, s to −∞, ∞.…”

Section: Dominant Fsi Parts In the Response For Smooth And Singulmentioning

confidence: 99%

Beyond the binary collision approximation for the large-qresponse of liquid4He

Rinat

Taragin²

1998

Phys. Rev. B

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We discuss corrections to the linear response of a many-body system beyond the binary collision approximation. We first derive for smooth pair interactions an exact expression of the response ∝ 1/q 2 , considerably simplifying existing forms and present also the generalization for interactions with a strong, short-range repulsion. We then apply the latter to the case of liquid 4 He. We display the numerical influence of the 1/q 2 correction around the quasi-elastic peak and in the low-intensity wings of the response, far from that peak. Finally we resolve an apparent contradiction in previous discussions around the fourth order cumulant expansion coefficient. Our results prove that the large-q response of liquid 4 He can be accurately understood on the basis of a dynamical theory.

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“…The dominant contributions to the FSE are well accounted for by the different theoretical methods [14][15][16] used in their study with an overall agreement for qտ16 Å Ϫ1 . [17][18][19] Using the theoretical prediction for the FSE and the IRE associated to the precision of the measurements, DINS in superfluid 4 He points to a condensate fraction n 0 ϭ9.2Ϯ1.1 and a single-particle kinetic energy T/Nϭ14.5Ϯ0.5 K. 20 Both values are in a nice agreement with the theoretical values obtained with Green's function Monte Carlo ͑GFMC͒, 21 diffusion Monte Carlo ͑DMC͒, 22 and path integral Monte Carlo 23 ͑PIMC͒ methods.…”

Section: Introductionmentioning

confidence: 99%

High-momentum dynamic structure function of liquid3He−4Hemixtures: A microscopic approach

2001

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The high-momentum dynamic structure function of liquid 3 He- 4 He mixtures has been studied introducing final-state effects. Corrections to the impulse approximation have been included using a generalized GerschRodriguez theory that properly takes into account the Fermi statistics of 3 He atoms. The microscopic inputs, as the momentum distributions and the two-body density matrices, correspond to a variational ͑fermi͒-hypernetted chain calculation. The agreement with experimental data obtained at qϭ23.1 Å Ϫ1 is not completely satisfactory, the comparison being difficult due to inconsistencies present in the scattering measurements. The significant differences between the experimental determinations and the theoretical results for the 4 He condensate fraction and the 3 He kinetic energy still remain unsolved.

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Large-qneutron inclusive-scattering data from liquid4He

Cited by 17 publications

References 32 publications

Condensate, momentum distribution, and final-state effects in liquid4He

Condensate, momentum distribution, and final-state effects in liquid4He

Beyond the binary collision approximation for the large-qresponse of liquid4He

High-momentum dynamic structure function of liquid3He−4Hemixtures: A microscopic approach

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