# Quantum Phase Transition in a Two-Dimensional System of Dipoles

## Abstract

The ground-state phase diagram of a two-dimensional Bose system with dipole-dipole interactions is studied by means of a quantum Monte Carlo technique. Our calculation predicts a quantum phase transition from a gas to a solid phase when the density increases. In the gas phase, the condensate fraction is calculated as a function of the density. Using the Feynman approximation, the collective excitation branch is studied and the appearance of a roton minimum is observed. The results of the static structure factor at both sides of the gas-solid phase are also presented. The Lindemann ratio at the transition point becomes {gamma}=0.230(6). The condensate fraction in the gas phase is estimated as a function of the density.

- Authors:

- Departament de Fisica i Enginyeria Nuclear, Campus Nord B4-B5, Universitat Politecnica de Catalunya, E-08034 Barcelona (Spain)
- Institute of Spectroscopy, 142190 Troitsk (Russian Federation)

- Publication Date:

- OSTI Identifier:
- 20955436

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Physical Review Letters; Journal Volume: 98; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevLett.98.060405; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 36 MATERIALS SCIENCE; APPROXIMATIONS; COLLECTIVE EXCITATIONS; DIPOLES; GROUND STATES; MONTE CARLO METHOD; PHASE DIAGRAMS; PHASE TRANSFORMATIONS; STRUCTURE FACTORS; TWO-DIMENSIONAL CALCULATIONS

### Citation Formats

```
Astrakharchik, G. E., Boronat, J., Kurbakov, I. L., and Lozovik, Yu. E..
```*Quantum Phase Transition in a Two-Dimensional System of Dipoles*. United States: N. p., 2007.
Web. doi:10.1103/PHYSREVLETT.98.060405.

```
Astrakharchik, G. E., Boronat, J., Kurbakov, I. L., & Lozovik, Yu. E..
```*Quantum Phase Transition in a Two-Dimensional System of Dipoles*. United States. doi:10.1103/PHYSREVLETT.98.060405.

```
Astrakharchik, G. E., Boronat, J., Kurbakov, I. L., and Lozovik, Yu. E.. Fri .
"Quantum Phase Transition in a Two-Dimensional System of Dipoles". United States.
doi:10.1103/PHYSREVLETT.98.060405.
```

```
@article{osti_20955436,
```

title = {Quantum Phase Transition in a Two-Dimensional System of Dipoles},

author = {Astrakharchik, G. E. and Boronat, J. and Kurbakov, I. L. and Lozovik, Yu. E.},

abstractNote = {The ground-state phase diagram of a two-dimensional Bose system with dipole-dipole interactions is studied by means of a quantum Monte Carlo technique. Our calculation predicts a quantum phase transition from a gas to a solid phase when the density increases. In the gas phase, the condensate fraction is calculated as a function of the density. Using the Feynman approximation, the collective excitation branch is studied and the appearance of a roton minimum is observed. The results of the static structure factor at both sides of the gas-solid phase are also presented. The Lindemann ratio at the transition point becomes {gamma}=0.230(6). The condensate fraction in the gas phase is estimated as a function of the density.},

doi = {10.1103/PHYSREVLETT.98.060405},

journal = {Physical Review Letters},

number = 6,

volume = 98,

place = {United States},

year = {Fri Feb 09 00:00:00 EST 2007},

month = {Fri Feb 09 00:00:00 EST 2007}

}

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