## Diffusion Monte Carlo study of strongly interacting two-dimensional Fermi gases

## Abstract

Ultracold atomic Fermi gases have been a popular topic of research, with attention being paid recently to two-dimensional (2D) gases. In this work, we perform T=0 *ab initio* diffusion Monte Carlo calculations for a strongly interacting two-component Fermi gas confined to two dimensions. We first go over finite-size systems and the connection to the thermodynamic limit. After that, we illustrate pertinent 2D scattering physics and properties of the wave function. We then show energy results for the strong-coupling crossover, in between the Bose-Einstein condensation (BEC) and Bardeen-Cooper-Schrieffer (BCS) regimes. Our energy results for the BEC-BCS crossover are parametrized to produce an equation of state, which is used to determine Tan's contact. We carry out a detailed comparison with other microscopic results. Lastly, we calculate the pairing gap for a range of interaction strengths in the strong coupling regime, following from variationally optimized many-body wave functions.

- Authors:

- Univ. of Guelph, Guelph, ON (Canada)
- Univ. of Guelph, Guelph, ON (Canada); Univ. of Waterloo, Waterloo, ON (Canada)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

- Publication Date:

- Research Org.:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 1335626

- Alternate Identifier(s):
- OSTI ID: 1236542

- Report Number(s):
- LA-UR-15-28921

Journal ID: ISSN 2469-9926; PLRAAN

- Grant/Contract Number:
- AC52-06NA25396

- Resource Type:
- Accepted Manuscript

- Journal Name:
- Physical Review A

- Additional Journal Information:
- Journal Volume: 93; Journal Issue: 2; Journal ID: ISSN 2469-9926

- Publisher:
- American Physical Society (APS)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 74 ATOMIC AND MOLECULAR PHYSICS; 97 MATHEMATICS AND COMPUTING; atomic and nuclear physics

### Citation Formats

```
Galea, Alexander, Dawkins, Hillary, Gandolfi, Stefano, and Gezerlis, Alexandros. Diffusion Monte Carlo study of strongly interacting two-dimensional Fermi gases. United States: N. p., 2016.
Web. doi:10.1103/PhysRevA.93.023602.
```

```
Galea, Alexander, Dawkins, Hillary, Gandolfi, Stefano, & Gezerlis, Alexandros. Diffusion Monte Carlo study of strongly interacting two-dimensional Fermi gases. United States. doi:10.1103/PhysRevA.93.023602.
```

```
Galea, Alexander, Dawkins, Hillary, Gandolfi, Stefano, and Gezerlis, Alexandros. Mon .
"Diffusion Monte Carlo study of strongly interacting two-dimensional Fermi gases". United States. doi:10.1103/PhysRevA.93.023602. https://www.osti.gov/servlets/purl/1335626.
```

```
@article{osti_1335626,
```

title = {Diffusion Monte Carlo study of strongly interacting two-dimensional Fermi gases},

author = {Galea, Alexander and Dawkins, Hillary and Gandolfi, Stefano and Gezerlis, Alexandros},

abstractNote = {Ultracold atomic Fermi gases have been a popular topic of research, with attention being paid recently to two-dimensional (2D) gases. In this work, we perform T=0 ab initio diffusion Monte Carlo calculations for a strongly interacting two-component Fermi gas confined to two dimensions. We first go over finite-size systems and the connection to the thermodynamic limit. After that, we illustrate pertinent 2D scattering physics and properties of the wave function. We then show energy results for the strong-coupling crossover, in between the Bose-Einstein condensation (BEC) and Bardeen-Cooper-Schrieffer (BCS) regimes. Our energy results for the BEC-BCS crossover are parametrized to produce an equation of state, which is used to determine Tan's contact. We carry out a detailed comparison with other microscopic results. Lastly, we calculate the pairing gap for a range of interaction strengths in the strong coupling regime, following from variationally optimized many-body wave functions.},

doi = {10.1103/PhysRevA.93.023602},

journal = {Physical Review A},

number = 2,

volume = 93,

place = {United States},

year = {2016},

month = {2}

}

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