Stable structures of He and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi mathvariant="normal">H</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mi mathvariant="normal">O</mml:mi></mml:mrow></mml:math>at high pressure

Liu, Hanyu; Yao, Yansun; Klug, D. D.

doi:10.1103/physrevb.91.014102

Cited by 69 publications

(45 citation statements)

References 33 publications

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“…The large-N based theories, when applied to atomic Bose gases, are derivable from well-defined thermodynamic free energies, show a smooth second-order BEC transition, and are consistent with standard perturbation theory or renormalization analysis in low-temperature and weakly-interacting regimes [12][13][14][15]. The normal state properties from the large-N expansion also compare favorable with Monte-Carlo simulations [16].…”

Section: Introductionsupporting

confidence: 59%

Critical temperature of trapped interacting bosons from large-N-based theories

Kim

Chien

2016

Phys. Rev. A

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Ultracold atoms provide clues to an important many-body problem regarding the dependence of Bose-Einstein condensation (BEC) transition temperature Tc on interactions. However, cold atoms are trapped in harmonic potentials and theoretical evaluations of the Tc shift of trapped interacting Bose gases are challenging. While previous predictions of the leading-order shift have been confirmed, more recent experiments exhibit higherorder corrections beyond available mean-field theories. By implementing two large-N based theories with the local density approximation (LDA), we extract next-order corrections of the Tc shift. The leading-order large-N theory produces results quantitatively different from the latest experimental data. The leading-order auxiliary field (LOAF) theory containing both normal and anomalous density fields captures the Tc shift accurately in the weak interaction regime. However, the LOAF theory shows incompatible behavior with the LDA and forcing the LDA leads to density discontinuities in the trap profiles. We present a phenomenological model based on the LOAF theory, which repairs the incompatibility and provides a prediction of the Tc shift in stronger interaction regime.arXiv:1512.08446v1 [cond-mat.quant-gas]

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Section: Introductionsupporting

confidence: 59%

Critical temperature of trapped interacting bosons from large-N-based theories

Kim

Chien

2016

Phys. Rev. A

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“…The notion that noble gases do not form stable chemical compounds was dispelled long ago by the discovery of stable xenon and krypton compounds . High pressure (HP) drastically changes element and compound properties, and has stimulated theoretical studies on the possibility of noble gases, including helium, forming stable compounds under pressure . One such prediction has recently been confirmed experimentally and a stable Na 2 He electride that crystallizes in a fluorite‐type crystal structure was obtained above 113 GPa .…”

Section: Introductionmentioning

confidence: 99%

How and Why Does Helium Permeate Nonporous Arsenolite Under High Pressure?

et al. 2018

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Investigations into the helium permeation of arsenolite, the cubic, molecular arsenic(III) oxide polymorph As O , were carried out to understand how and why arsenolite helium clathrate As O ⋅2 He is formed. High-pressure synchrotron X-ray diffraction experiments on arsenolite single crystals revealed that the permeation of helium into nonporous arsenolite depends on the time for which the crystal is subjected to high pressure and on the crystal history. The single crystal was totally transformed into As O ⋅2 He within 45 h under 5 GPa. After release of the pressure, arsenolite was recovered and a repeated increase in pressure up to 3 GPa led to practically instant As O ⋅2 He formation. However, when a pristine arsenolite single crystal was quickly subjected to a pressure of 13 GPa, no helium permeation was observed at all. No neon permeation was observed in analogous experiments. Quantum mechanical computations indicate that there are no specific attractive interactions between He atoms and As O molecules at the distances observed in the As O ⋅2 He crystal structure. Detailed analysis of As O molecular structure changes has shown that the introduction of He into the arsenolite crystal lattice significantly reduces molecular deformations by decreasing the anisotropy of stress exerted on the As O molecules. This effect and the pΔV term, rather than any specific As⋅⋅⋅He binding, are the driving forces for the formation As O ⋅2 He.

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“…The large-N expansion in the context of Bose systems' theory was previously used in different variations including summation of diagrams in a particle-hole channel for the Galilean-invariant [13,14], relativistic [15], and twocomponent [16] many-boson systems as well as ladder summation of particle-particle diagrams for the normal state Bose gases [17], but the full numerical analysis of the problem at finite temperatures in the Bose condensed phase is lacking. The application of this method to two-dimensional Bose systems [18] revealed very interesting phenomenon, namely, the appearance of thermallystimulated roton minimum in the spectrum of collective excitations.…”

Section: Introductionmentioning

confidence: 99%