7 Sep 2013 | M. Aidelsburger1,2, M. Atala1,2, M. Lohse1,2, J. T. Barreiro1,2, B. Paredes3 and I. Bloch1,2
This paper presents the experimental realization of an optical lattice that enables the generation of large, homogeneous, and tunable artificial magnetic fields using ultracold atoms. The technique involves laser-assisted tunneling in a tilted optical potential, which creates spatially dependent complex tunneling amplitudes. This results in atoms accumulating a phase shift equivalent to the Aharonov-Bohm phase of charged particles in a magnetic field. The system is shown to be described by the Hofstadter model, with the local distribution of fluxes determined by observing cyclotron orbits of atoms on lattice plaquettes. Additionally, the system naturally realizes the time-reversal symmetric Hamiltonian underlying the quantum spin Hall effect, with opposite magnetic fields experienced by spin-up and spin-down atoms.
Ultracold atoms in optical lattices provide a unique platform to study condensed matter Hamiltonians in a clean and controlled environment. The paper highlights the potential of these systems to realize and probe topological phases of matter, particularly through quantum optical techniques. The Hofstadter-Harper Hamiltonian, which describes electrons in a periodic potential under a large magnetic field, is of particular interest. For a filled band of fermions, this model realizes the quantum Hall insulator, a topological insulator that breaks time-reversal symmetry.
The challenge of simulating orbital magnetism in ultracold quantum gases is hindered by the charge neutrality of atoms, which prevents them from experiencing a Lorentz force. Synthetic gauge potentials have been developed to overcome this limitation, including the use of the Coriolis force in rotating gases and Berry phases via Raman lasers. Recent advances include the creation of staggered magnetic fields in optical lattices using laser-induced tunneling or dynamical shaking. In one dimension, tunable gauge fields have been implemented in an effective "Zeeman lattice" or using periodic driving. The free-space spin Hall effect has also been observed using Raman dressing.
The paper demonstrates the first experimental realization of an optical lattice that allows for the generation of large tunable homogeneous artificial magnetic fields. The technique is based on previous work on staggered magnetic fields. The main idea is closely related to early proposals by Jaksch and Zoller. The method does not rely on the internal structure of the atom, making it applicable to a wide range of atomic species, including fermionic atoms. Laser-assisted tunneling in a tilted optical lattice is used, with periodic driving and far-detuned running-wave beams. This method minimizes heating due to spontaneous emission, allowing for precise control of the system.
The experimental setup involves ultracold rubidium atoms in a three-dimensional optical lattice. A magnetic field gradient is used to generate a linear potential between neighboring sites, and two Zeeman states with opposite magnetic moments are used to create spin-up and spin-down atoms. The system is shown to realize a non-Abelian SU(2) gauge field, resulting in opposite magnetic fields for spin-upThis paper presents the experimental realization of an optical lattice that enables the generation of large, homogeneous, and tunable artificial magnetic fields using ultracold atoms. The technique involves laser-assisted tunneling in a tilted optical potential, which creates spatially dependent complex tunneling amplitudes. This results in atoms accumulating a phase shift equivalent to the Aharonov-Bohm phase of charged particles in a magnetic field. The system is shown to be described by the Hofstadter model, with the local distribution of fluxes determined by observing cyclotron orbits of atoms on lattice plaquettes. Additionally, the system naturally realizes the time-reversal symmetric Hamiltonian underlying the quantum spin Hall effect, with opposite magnetic fields experienced by spin-up and spin-down atoms.
Ultracold atoms in optical lattices provide a unique platform to study condensed matter Hamiltonians in a clean and controlled environment. The paper highlights the potential of these systems to realize and probe topological phases of matter, particularly through quantum optical techniques. The Hofstadter-Harper Hamiltonian, which describes electrons in a periodic potential under a large magnetic field, is of particular interest. For a filled band of fermions, this model realizes the quantum Hall insulator, a topological insulator that breaks time-reversal symmetry.
The challenge of simulating orbital magnetism in ultracold quantum gases is hindered by the charge neutrality of atoms, which prevents them from experiencing a Lorentz force. Synthetic gauge potentials have been developed to overcome this limitation, including the use of the Coriolis force in rotating gases and Berry phases via Raman lasers. Recent advances include the creation of staggered magnetic fields in optical lattices using laser-induced tunneling or dynamical shaking. In one dimension, tunable gauge fields have been implemented in an effective "Zeeman lattice" or using periodic driving. The free-space spin Hall effect has also been observed using Raman dressing.
The paper demonstrates the first experimental realization of an optical lattice that allows for the generation of large tunable homogeneous artificial magnetic fields. The technique is based on previous work on staggered magnetic fields. The main idea is closely related to early proposals by Jaksch and Zoller. The method does not rely on the internal structure of the atom, making it applicable to a wide range of atomic species, including fermionic atoms. Laser-assisted tunneling in a tilted optical lattice is used, with periodic driving and far-detuned running-wave beams. This method minimizes heating due to spontaneous emission, allowing for precise control of the system.
The experimental setup involves ultracold rubidium atoms in a three-dimensional optical lattice. A magnetic field gradient is used to generate a linear potential between neighboring sites, and two Zeeman states with opposite magnetic moments are used to create spin-up and spin-down atoms. The system is shown to realize a non-Abelian SU(2) gauge field, resulting in opposite magnetic fields for spin-up