2023
Yao, Ruixiao; Chi, Sungjae; Mukherjee, Biswaroop; Shaffer, Airlia; Zwierlein, Martin; Fletcher, Richard J.
Observation of chiral edge transport in a rapidly-rotating quantum gas Miscellaneous
2023.
@misc{yao2023observation,
title = {Observation of chiral edge transport in a rapidly-rotating quantum gas},
author = {Ruixiao Yao and Sungjae Chi and Biswaroop Mukherjee and Airlia Shaffer and Martin Zwierlein and Richard J. Fletcher},
year = {2023},
date = {2023-01-01},
keywords = {},
pubstate = {published},
tppubtype = {misc}
}
Yao, Ruixiao; Chi, Sungjae; Mukherjee, Biswaroop; Shaffer, Airlia; Zwierlein, Martin; Fletcher, Richard J.
Observation of chiral edge transport in a rapidly-rotating quantum gas Miscellaneous
2023.
@misc{yao2023observationb,
title = {Observation of chiral edge transport in a rapidly-rotating quantum gas},
author = {Ruixiao Yao and Sungjae Chi and Biswaroop Mukherjee and Airlia Shaffer and Martin Zwierlein and Richard J. Fletcher},
year = {2023},
date = {2023-01-01},
keywords = {},
pubstate = {published},
tppubtype = {misc}
}
2022
Mukherjee, Biswaroop; Shaffer, Airlia; Patel, Parth B.; Yan, Zhenjie; Wilson, Cedric C.; Crépel, Valentin; Fletcher, Richard J.; Zwierlein, Martin
Crystallization of bosonic quantum Hall states in a rotating quantum gas Journal Article
In: Nature, vol. 601, no. 7891, pp. 58–62, 2022, ISBN: 1476-4687.
@article{<LineBreak>Mukherjee2022,
title = {Crystallization of bosonic quantum Hall states in a rotating quantum gas},
author = {Biswaroop Mukherjee and Airlia Shaffer and Parth B. Patel and Zhenjie Yan and Cedric C. Wilson and Valentin Crépel and Richard J. Fletcher and Martin Zwierlein},
url = {https://doi.org/10.1038/s41586-021-04170-2},
doi = {10.1038/s41586-021-04170-2},
isbn = {1476-4687},
year = {2022},
date = {2022-01-01},
urldate = {2022-01-01},
journal = {Nature},
volume = {601},
number = {7891},
pages = {58--62},
abstract = {The dominance of interactions over kinetic energy lies at the heart of strongly correlated quantum matter, from fractional quantum Hall liquids, to atoms in optical lattices and twisted bilayer graphene. Crystalline phases often compete with correlated quantum liquids, and transitions between them occur when the energy cost of forming a density wave approaches zero. A prime example occurs for electrons in high-strength magnetic fields, where the instability of quantum Hall liquids towards a Wigner crystal is heralded by a roton-like softening of density modulations at the magnetic length. Remarkably, interacting bosons in a gauge field are also expected to form analogous liquid and crystalline states. However, combining interactions with strong synthetic magnetic fields has been a challenge for experiments on bosonic quantum gases. Here we study the purely interaction-driven dynamics of a Landau gauge Bose-Einstein condensate in and near the lowest Landau level. We observe a spontaneous crystallization driven by condensation of magneto-rotons, excitations visible as density modulations at the magnetic length. Increasing the cloud density smoothly connects this behaviour to a quantum version of the Kelvin-Helmholtz hydrodynamic instability, driven by the sheared internal flow profile of the rapidly rotating condensate. At long times the condensate self-organizes into a persistent array of droplets separated by vortex streets, which are stabilized by a balance of interactions and effective magnetic forces.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The dominance of interactions over kinetic energy lies at the heart of strongly correlated quantum matter, from fractional quantum Hall liquids, to atoms in optical lattices and twisted bilayer graphene. Crystalline phases often compete with correlated quantum liquids, and transitions between them occur when the energy cost of forming a density wave approaches zero. A prime example occurs for electrons in high-strength magnetic fields, where the instability of quantum Hall liquids towards a Wigner crystal is heralded by a roton-like softening of density modulations at the magnetic length. Remarkably, interacting bosons in a gauge field are also expected to form analogous liquid and crystalline states. However, combining interactions with strong synthetic magnetic fields has been a challenge for experiments on bosonic quantum gases. Here we study the purely interaction-driven dynamics of a Landau gauge Bose-Einstein condensate in and near the lowest Landau level. We observe a spontaneous crystallization driven by condensation of magneto-rotons, excitations visible as density modulations at the magnetic length. Increasing the cloud density smoothly connects this behaviour to a quantum version of the Kelvin-Helmholtz hydrodynamic instability, driven by the sheared internal flow profile of the rapidly rotating condensate. At long times the condensate self-organizes into a persistent array of droplets separated by vortex streets, which are stabilized by a balance of interactions and effective magnetic forces.
2021
Fletcher, Richard J.; Shaffer, Airlia; Wilson, Cedric C.; Patel, Parth B.; Yan, Zhenjie; Crépel, Valentin; Mukherjee, Biswaroop; Zwierlein, Martin W.
Geometric squeezing into the lowest Landau level Journal Article
In: Science, vol. 372, no. 6548, pp. 1318-1322, 2021.
@article{doi:10.1126/science.aba7202,
title = {Geometric squeezing into the lowest Landau level},
author = {Richard J. Fletcher and Airlia Shaffer and Cedric C. Wilson and Parth B. Patel and Zhenjie Yan and Valentin Crépel and Biswaroop Mukherjee and Martin W. Zwierlein},
url = {https://www.science.org/doi/abs/10.1126/science.aba7202},
doi = {10.1126/science.aba7202 },
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Science},
volume = {372},
number = {6548},
pages = {1318-1322},
abstract = {Ultracold atomic gases are very good at simulating electrons in solids but lack one essential party trick: charge. Their neutrality makes it challenging to simulate phenomena such as the quantum Hall effect, which, in the case of charged electrons, is easily induced by an external magnetic field. One way to produce a similar effect in a neutral system is to rotate it, but achieving the equivalent of strong magnetic fields remains difficult. Fletcher et al. rotated a gas of trapped sodium atoms, reaching a state in which the gas could be described by a single lowest Landau-level wave-function. The system is expected to be a testbed for studying the behavior of strongly interacting many-body states. Science, aba7202, this issue p. 1318 A rotating Bose-Einstein condensate of sodium atoms is used to simulate the effects of high magnetic fields. The equivalence between particles under rotation and charged particles in a magnetic field relates phenomena as diverse as spinning atomic nuclei, weather patterns, and the quantum Hall effect. For such systems, quantum mechanics dictates that translations along different directions do not commute, implying a Heisenberg uncertainty relation between spatial coordinates. We implement squeezing of this geometric quantum uncertainty, resulting in a rotating Bose-Einstein condensate occupying a single Landau gauge wave function. We resolve the extent of zero-point cyclotron orbits and demonstrate geometric squeezing of the orbits’ centers 7 decibels below the standard quantum limit. The condensate attains an angular momentum exceeding 1000 quanta per particle and an interatomic distance comparable to the cyclotron orbit. This offers an alternative route toward strongly correlated bosonic fluids.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Ultracold atomic gases are very good at simulating electrons in solids but lack one essential party trick: charge. Their neutrality makes it challenging to simulate phenomena such as the quantum Hall effect, which, in the case of charged electrons, is easily induced by an external magnetic field. One way to produce a similar effect in a neutral system is to rotate it, but achieving the equivalent of strong magnetic fields remains difficult. Fletcher et al. rotated a gas of trapped sodium atoms, reaching a state in which the gas could be described by a single lowest Landau-level wave-function. The system is expected to be a testbed for studying the behavior of strongly interacting many-body states. Science, aba7202, this issue p. 1318 A rotating Bose-Einstein condensate of sodium atoms is used to simulate the effects of high magnetic fields. The equivalence between particles under rotation and charged particles in a magnetic field relates phenomena as diverse as spinning atomic nuclei, weather patterns, and the quantum Hall effect. For such systems, quantum mechanics dictates that translations along different directions do not commute, implying a Heisenberg uncertainty relation between spatial coordinates. We implement squeezing of this geometric quantum uncertainty, resulting in a rotating Bose-Einstein condensate occupying a single Landau gauge wave function. We resolve the extent of zero-point cyclotron orbits and demonstrate geometric squeezing of the orbits’ centers 7 decibels below the standard quantum limit. The condensate attains an angular momentum exceeding 1000 quanta per particle and an interatomic distance comparable to the cyclotron orbit. This offers an alternative route toward strongly correlated bosonic fluids.
2020
Patel, Parth B; Yan, Zhenjie; Mukherjee, Biswaroop; Fletcher, Richard J; Struck, Julian; Zwierlein, Martin W
Universal sound diffusion in a strongly interacting Fermi gas Journal Article
In: Science, vol. 370, no. 6521, pp. 1222–1226, 2020, ISSN: 0036-8075.
@article{Patel:2020,
title = {Universal sound diffusion in a strongly interacting Fermi gas},
author = {Parth B Patel and Zhenjie Yan and Biswaroop Mukherjee and Richard J Fletcher and Julian Struck and Martin W Zwierlein},
url = {https://science.sciencemag.org/content/370/6521/1222},
doi = {10.1126/science.aaz5756},
issn = {0036-8075},
year = {2020},
date = {2020-01-01},
journal = {Science},
volume = {370},
number = {6521},
pages = {1222--1226},
publisher = {American Association for the Advancement of Science},
abstract = {A gas of strongly interacting fermionic atoms can serve as a model for systems with densities and energies spanning many orders of magnitude. This universality of physics comes about thanks to a property known as scale invariance. Patel et al. exploited this concept to draw universal conclusions about the attenuation of sound in such systems by studying a homogeneous gas of lithium-6 atoms at very low temperatures (see the Perspective by Schaefer). They found that below the superfluid transition, the sound diffusivity behaved not unlike what has been observed in helium-4, a fluid of strongly interacting bosons.Science, this issue p. 1222; see also p. 1162Transport of strongly interacting fermions is crucial for the properties of modern materials, nuclear fission, the merging of neutron stars, and the expansion of the early Universe. Here, we observe a universal quantum limit of diffusivity in a homogeneous, strongly interacting atomic Fermi gas by studying sound propagation and its attenuation through the coupled transport of momentum and heat. In the normal state, the sound diffusivity D monotonically decreases upon lowering the temperature, in contrast to the diverging behavior of weakly interacting Fermi liquids. Below the superfluid transition temperature, D attains a universal value set by the ratio of Plancktextquoterights constant and the particle mass. Our findings inform theories of fermion transport, with relevance for hydrodynamic flow of electrons, neutrons, and quarks.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A gas of strongly interacting fermionic atoms can serve as a model for systems with densities and energies spanning many orders of magnitude. This universality of physics comes about thanks to a property known as scale invariance. Patel et al. exploited this concept to draw universal conclusions about the attenuation of sound in such systems by studying a homogeneous gas of lithium-6 atoms at very low temperatures (see the Perspective by Schaefer). They found that below the superfluid transition, the sound diffusivity behaved not unlike what has been observed in helium-4, a fluid of strongly interacting bosons.Science, this issue p. 1222; see also p. 1162Transport of strongly interacting fermions is crucial for the properties of modern materials, nuclear fission, the merging of neutron stars, and the expansion of the early Universe. Here, we observe a universal quantum limit of diffusivity in a homogeneous, strongly interacting atomic Fermi gas by studying sound propagation and its attenuation through the coupled transport of momentum and heat. In the normal state, the sound diffusivity D monotonically decreases upon lowering the temperature, in contrast to the diverging behavior of weakly interacting Fermi liquids. Below the superfluid transition temperature, D attains a universal value set by the ratio of Plancktextquoterights constant and the particle mass. Our findings inform theories of fermion transport, with relevance for hydrodynamic flow of electrons, neutrons, and quarks.
2019
Mukherjee, Biswaroop; Patel, Parth B; Yan, Zhenjie; Fletcher, Richard J; Struck, Julian; Zwierlein, Martin W
Spectral Response and Contact of the Unitary Fermi Gas Journal Article
In: Phys. Rev. Lett., vol. 122, pp. 203402, 2019.
@article{Mukherjee:2019,
title = {Spectral Response and Contact of the Unitary Fermi Gas},
author = {Biswaroop Mukherjee and Parth B Patel and Zhenjie Yan and Richard J Fletcher and Julian Struck and Martin W Zwierlein},
url = {https://link.aps.org/doi/10.1103/PhysRevLett.122.203402},
doi = {10.1103/PhysRevLett.122.203402},
year = {2019},
date = {2019-05-01},
journal = {Phys. Rev. Lett.},
volume = {122},
pages = {203402},
publisher = {American Physical Society},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Yan, Zhenjie; Patel, Parth B; Mukherjee, Biswaroop; Fletcher, Richard J; Struck, Julian; Zwierlein, Martin W
Boiling a Unitary Fermi Liquid Journal Article
In: Phys. Rev. Lett., vol. 122, pp. 093401, 2019.
@article{Yan:2019,
title = {Boiling a Unitary Fermi Liquid},
author = {Zhenjie Yan and Parth B Patel and Biswaroop Mukherjee and Richard J Fletcher and Julian Struck and Martin W Zwierlein},
url = {https://link.aps.org/doi/10.1103/PhysRevLett.122.093401},
doi = {10.1103/PhysRevLett.122.093401},
year = {2019},
date = {2019-03-01},
journal = {Phys. Rev. Lett.},
volume = {122},
pages = {093401},
publisher = {American Physical Society},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2018
Fletcher, Richard J; Man, Jay; Lopes, Raphael; Christodoulou, Panagiotis; Schmitt, Julian; Sohmen, Maximilian; Navon, Nir; Smith, Robert P; Hadzibabic, Zoran
Elliptic flow in a strongly interacting normal Bose gas Journal Article
In: Phys. Rev. A, vol. 98, pp. 011601, 2018.
@article{Fletcher:2018,
title = {Elliptic flow in a strongly interacting normal Bose gas},
author = {Richard J Fletcher and Jay Man and Raphael Lopes and Panagiotis Christodoulou and Julian Schmitt and Maximilian Sohmen and Nir Navon and Robert P Smith and Zoran Hadzibabic},
url = {https://link.aps.org/doi/10.1103/PhysRevA.98.011601},
doi = {10.1103/PhysRevA.98.011601},
year = {2018},
date = {2018-07-01},
journal = {Phys. Rev. A},
volume = {98},
pages = {011601},
publisher = {American Physical Society},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2017
Fletcher, Richard J; Lopes, Raphael; Man, Jay; Navon, Nir; Smith, Robert P; Zwierlein, Martin W; Hadzibabic, Zoran
Two- and three-body contacts in the unitary Bose gas Journal Article
In: Science, vol. 355, no. 6323, pp. 377–380, 2017, ISSN: 0036-8075.
@article{Fletcher:2017,
title = {Two- and three-body contacts in the unitary Bose gas},
author = {Richard J Fletcher and Raphael Lopes and Jay Man and Nir Navon and Robert P Smith and Martin W Zwierlein and Zoran Hadzibabic},
url = {https://science.sciencemag.org/content/355/6323/377},
doi = {10.1126/science.aai8195},
issn = {0036-8075},
year = {2017},
date = {2017-01-01},
journal = {Science},
volume = {355},
number = {6323},
pages = {377--380},
publisher = {American Association for the Advancement of Science},
abstract = {Tunable interactions make dilute atomic gases ideal for studying the collective dynamics of many-body systems. If the gas consists of strongly interacting fermions evenly divided into two groups of opposite spin, many of its properties can be distilled to two-body correlations. Fletcher et al. show that this does not hold for a gas of bosons, where identical particles happily congregate. The researchers measured a quantity that, in a thermal resonantly interacting Bose gas, depends only on three-body correlations. This enabled them to quantify the elusive correlations and establish unambiguously their effect on the physics of the many-body state.Science, this issue p. 377In many-body systems governed by pairwise contact interactions, a wide range of observables is linked by a single parameter, the two-body contact, which quantifies two-particle correlations. This profound insight has transformed our understanding of strongly interacting Fermi gases. Using Ramsey interferometry, we studied coherent evolution of the resonantly interacting Bose gas, and we show here that it cannot be explained by only pairwise correlations. Our experiments reveal the crucial role of three-body correlations arising from Efimov physics and provide a direct measurement of the associated three-body contact.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Tunable interactions make dilute atomic gases ideal for studying the collective dynamics of many-body systems. If the gas consists of strongly interacting fermions evenly divided into two groups of opposite spin, many of its properties can be distilled to two-body correlations. Fletcher et al. show that this does not hold for a gas of bosons, where identical particles happily congregate. The researchers measured a quantity that, in a thermal resonantly interacting Bose gas, depends only on three-body correlations. This enabled them to quantify the elusive correlations and establish unambiguously their effect on the physics of the many-body state.Science, this issue p. 377In many-body systems governed by pairwise contact interactions, a wide range of observables is linked by a single parameter, the two-body contact, which quantifies two-particle correlations. This profound insight has transformed our understanding of strongly interacting Fermi gases. Using Ramsey interferometry, we studied coherent evolution of the resonantly interacting Bose gas, and we show here that it cannot be explained by only pairwise correlations. Our experiments reveal the crucial role of three-body correlations arising from Efimov physics and provide a direct measurement of the associated three-body contact.
2015
Fletcher, Richard J; Robert-de-Saint-Vincent, Martin; Man, Jay; Navon, Nir; Smith, Robert P; Viebahn, Konrad G H; Hadzibabic, Zoran
Connecting Berezinskii-Kosterlitz-Thouless and BEC Phase Transitions by Tuning Interactions in a Trapped Gas Journal Article
In: Phys. Rev. Lett., vol. 114, pp. 255302, 2015.
@article{Fletcher:2015,
title = {Connecting Berezinskii-Kosterlitz-Thouless and BEC Phase Transitions by Tuning Interactions in a Trapped Gas},
author = {Richard J Fletcher and Martin Robert-de-Saint-Vincent and Jay Man and Nir Navon and Robert P Smith and Konrad G H Viebahn and Zoran Hadzibabic},
url = {https://link.aps.org/doi/10.1103/PhysRevLett.114.255302},
doi = {10.1103/PhysRevLett.114.255302},
year = {2015},
date = {2015-06-01},
journal = {Phys. Rev. Lett.},
volume = {114},
pages = {255302},
publisher = {American Physical Society},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2013
Fletcher, Richard J; Gaunt, Alexander L; Navon, Nir; Smith, Robert P; Hadzibabic, Zoran
Stability of a Unitary Bose Gas Journal Article
In: Phys. Rev. Lett., vol. 111, pp. 125303, 2013.
@article{Fletcher:2013,
title = {Stability of a Unitary Bose Gas},
author = {Richard J Fletcher and Alexander L Gaunt and Nir Navon and Robert P Smith and Zoran Hadzibabic},
url = {https://link.aps.org/doi/10.1103/PhysRevLett.111.125303},
doi = {10.1103/PhysRevLett.111.125303},
year = {2013},
date = {2013-09-01},
journal = {Phys. Rev. Lett.},
volume = {111},
pages = {125303},
publisher = {American Physical Society},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Gaunt, Alexander L; Fletcher, Richard J; Smith, Robert P; Hadzibabic, Zoran
A superheated Bose-condensed gas Journal Article
In: Nature Physics, vol. 9, no. 5, pp. 271–274, 2013, ISBN: 1745-2481.
@article{Gaunt:2013,
title = {A superheated Bose-condensed gas},
author = {Alexander L Gaunt and Richard J Fletcher and Robert P Smith and Zoran Hadzibabic},
url = {https://doi.org/10.1038/nphys2587},
doi = {10.1038/nphys2587},
isbn = {1745-2481},
year = {2013},
date = {2013-01-01},
journal = {Nature Physics},
volume = {9},
number = {5},
pages = {271--274},
abstract = {A Bose--Einstein condensate can exist in a superheated state well above the critical temperature if the interaction strength is tuned low. When the interactions are switched back on, the condensate boils away.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A Bose--Einstein condensate can exist in a superheated state well above the critical temperature if the interaction strength is tuned low. When the interactions are switched back on, the condensate boils away.
Beattie, Scott; Moulder, Stuart; Fletcher, Richard J; Hadzibabic, Zoran
Persistent Currents in Spinor Condensates Journal Article
In: Phys. Rev. Lett., vol. 110, pp. 025301, 2013.
@article{Beattie:2013,
title = {Persistent Currents in Spinor Condensates},
author = {Scott Beattie and Stuart Moulder and Richard J Fletcher and Zoran Hadzibabic},
url = {https://link.aps.org/doi/10.1103/PhysRevLett.110.025301},
doi = {10.1103/PhysRevLett.110.025301},
year = {2013},
date = {2013-01-01},
journal = {Phys. Rev. Lett.},
volume = {110},
pages = {025301},
publisher = {American Physical Society},
keywords = {},
pubstate = {published},
tppubtype = {article}
}