We evaluate the impact that nonlinear Zeeman shifts have on resonant radio-frequency (RF) dressed traps in an atom-chip configuration. The degeneracy of the resonance between Zeeman levels is lifted at large intensities of a static field, modifying the spatial dependence of the atomic adiabatic potential. In this context, we find effects that are important for the next generation of atom chips with tight trapping: in particular, that the vibrational frequency of the atom trap is sensitive to the RF frequency and, depending on the sign of the Landé factor, can produce significantly weaker, or tighter trapping when compared to the linear regime of the Zeeman effect. We take 87 Rb as an example and find that it is possible for the trapping frequency on F = 1 to exceed that of the F = 2 hyperfine manifold.We evaluate the impact that nonlinear Zeeman shifts have on resonant radio-frequency (RF) dressed traps in an atom-chip configuration. The degeneracy of the resonance between Zeeman levels is lifted at large intensities of a static field, modifying the spatial dependence of the atomic adiabatic potential. In this context, we find effects that are important for the next generation of atom chips with tight trapping: in particular, that the vibrational frequency of the atom trap is sensitive to the RF frequency and, depending on the sign of the Landé factor, can produce significantly weaker, or tighter trapping when compared to the linear regime of the Zeeman effect. We take 87 Rb as an example and find that it is possible for the trapping frequency on F = 1 to exceed that of the F = 2 hyperfine manifold.

Dec 7, 20128 citations

Trapping of Neutral Atoms with a Radio-Frequency Field

Haichao Zhang, Zhang Peng-Fei, Xinping Xu +2 more

Based on the dressed-atom approach, we discuss a two-dimensional (2D) radio-frequency trap for neutral atoms, in which the trap potential derives from the magnetic-dipole transitions among the hyperfine Zeeman sublevels. By adjusting the detuning of the radiation from resonance, the trapping states will be changed predominantly from the bare states of m F g F >0 to other states of m F g F <0, where m F and g F are the quantum numbers of Zeeman sublevels and the Landé factor, respectively. This character contrasts finely with that of a static magnetic trap that can only trap or guide the states of m F g F >0. In comparison to the optical field, the radio-frequency trap eliminates the spontaneous emission heating of the atoms. Unlike other oscillating traps reported in the literature, the configuration of the radio-frequency trap is suitable for realization of a miniature magnetic guide.Based on the dressed-atom approach, we discuss a two-dimensional (2D) radio-frequency trap for neutral atoms, in which the trap potential derives from the magnetic-dipole transitions among the hyperfine Zeeman sublevels. By adjusting the detuning of the radiation from resonance, the trapping states will be changed predominantly from the bare states of m F g F >0 to other states of m F g F <0, where m F and g F are the quantum numbers of Zeeman sublevels and the Landé factor, respectively. This character contrasts finely with that of a static magnetic trap that can only trap or guide the states of m F g F >0. In comparison to the optical field, the radio-frequency trap eliminates the spontaneous emission heating of the atoms. Unlike other oscillating traps reported in the literature, the configuration of the radio-frequency trap is suitable for realization of a miniature magnetic guide.

Chinese Physics LettersDec 23, 20043 citations

State-dependent transport in RF-dressed atom chip potentials

Vilius Atkočius, Jamie J. Johnson, Rhys Morrison +4 more

The manipulation of ultracold atoms in radio-frequency (RF)-dressed potentials offers unique advantages over static magnetic traps, such as the ability to create more complex potential landscapes, better control of atomic states, and increased robustness to environmental noise. Among the accessible geometries, ring traps are particularly promising for atomic Sagnac interferometers, which can be used to measure rotational motion with high sensitivity. Here, the authors demonstrate the state-dependent transport of atoms in an RF-dressed ring trap on an atom chip. By exploiting the polarization-dependent coupling of RF fields to different atomic hyperfine states, the authors achieve controlled transport of atoms in opposite directions. This approach targets the development of compact, high-precision devices for applications in inertial navigation and rotation sensing.The manipulation of ultracold atoms in radio-frequency (RF)-dressed potentials offers unique advantages over static magnetic traps, such as the ability to create more complex potential landscapes, better control of atomic states, and increased robustness to environmental noise. Among the accessible geometries, ring traps are particularly promising for atomic Sagnac interferometers, which can be used to measure rotational motion with high sensitivity. Here, the authors demonstrate the state-dependent transport of atoms in an RF-dressed ring trap on an atom chip. By exploiting the polarization-dependent coupling of RF fields to different atomic hyperfine states, the authors achieve controlled transport of atoms in opposite directions. This approach targets the development of compact, high-precision devices for applications in inertial navigation and rotation sensing.

AVS Quantum ScienceApr 30, 20250 citations

Ultracold atoms in radio-frequency dressed potentials beyond the rotating-wave approximation

Sebastian Hofferberth, B. Fischer, Thorsten Schumm +2 more

We study dressed Bose-Einstein condensates in an atom chip radio-frequency trap. We show that in this system sufficiently strong dressing can be achieved to cause the widely used rotating-wave approximation (RWA) to break down. We present a full calculation of the atom-field coupling which shows that the non-RWA contributions quantitatively alter the shape of the emerging dressed adiabatic potentials. The non-RWA contributions furthermore lead to additional allowed transitions between dressed levels. We use rf spectroscopy of Bose-Einstein condensates trapped in the dressed state potentials to directly observe the transition from the RWA to the beyond-RWA regime.We study dressed Bose-Einstein condensates in an atom chip radio-frequency trap. We show that in this system sufficiently strong dressing can be achieved to cause the widely used rotating-wave approximation (RWA) to break down. We present a full calculation of the atom-field coupling which shows that the non-RWA contributions quantitatively alter the shape of the emerging dressed adiabatic potentials. The non-RWA contributions furthermore lead to additional allowed transitions between dressed levels. We use rf spectroscopy of Bose-Einstein condensates trapped in the dressed state potentials to directly observe the transition from the RWA to the beyond-RWA regime.

arXiv:quant-ph/0611240Physical Review AJul 6, 200780 citations

Potential roughness suppression in a RF AC Zeeman atom chip trap

William Miyahira, S. Aubin

Trapping and manipulating ultracold atoms through the use of atom chips offers the ability to engineer complex electromagnetic field geometries in a compact form factor. One of the primary limitations hindering their use is trap potential roughness which arises as a result of defects in the atom chip wires when atoms are brought close to the chip. This roughness can play a limiting role in atom interferometry and strong 1D confinement experiments. We present an initial experimental demonstration of atom chip potential roughness suppression using radio-frequency (RF) AC Zeeman (ACZ) potentials on an atom chip. Using ∼20 MHz RF magnetic near-fields from the chip to target intra-manifold transitions in the 87Rb ground state, we trap atoms in a spindependent ACZ potential. We compare the axial trapping potential for atoms in comparable 2-wire DC and AC Zeeman traps and show evidence of roughness suppression in the AC trap.Trapping and manipulating ultracold atoms through the use of atom chips offers the ability to engineer complex electromagnetic field geometries in a compact form factor. One of the primary limitations hindering their use is trap potential roughness which arises as a result of defects in the atom chip wires when atoms are brought close to the chip. This roughness can play a limiting role in atom interferometry and strong 1D confinement experiments. We present an initial experimental demonstration of atom chip potential roughness suppression using radio-frequency (RF) AC Zeeman (ACZ) potentials on an atom chip. Using ∼20 MHz RF magnetic near-fields from the chip to target intra-manifold transitions in the 87Rb ground state, we trap atoms in a spindependent ACZ potential. We compare the axial trapping potential for atoms in comparable 2-wire DC and AC Zeeman traps and show evidence of roughness suppression in the AC trap.

Optical and Quantum Sensing and Precision Metrology IIMar 13, 20240 citations

Radio-frequency-induced ground-state degeneracy in a Bose-Einstein condensate of chromium atoms

Quentin Beaufils, T. Zanon-Willette, Radu Chicireanu +5 more

We study the effect of strong radio-frequency (rf) fields on a Bose-Einstein condensate (BEC) of chromium atoms, in a regime where the rf frequency is much larger than the Larmor frequency. We use the modification of the Land\'e factor by the rf field to bring all Zeeman states to degeneracy, despite the presence of a static magnetic field of up to $100\phantom{\rule{0.3em}{0ex}}\mathrm{mG}$ . This is demonstrated by analyzing the trajectories of the atoms under the influence of dressed magnetic potentials in the strong-field regime. We investigate the problem of adiabaticity of the rf dressing process and relate it to how close the dressed states are to degeneracy. Finally, we measure the lifetime of the rf dressed BECs and identify a rf-assisted two-body loss process induced by dipole-dipole interactions.We study the effect of strong radio-frequency (rf) fields on a Bose-Einstein condensate (BEC) of chromium atoms, in a regime where the rf frequency is much larger than the Larmor frequency. We use the modification of the Land\'e factor by the rf field to bring all Zeeman states to degeneracy, despite the presence of a static magnetic field of up to $100\phantom{\rule{0.3em}{0ex}}\mathrm{mG}$. This is demonstrated by analyzing the trajectories of the atoms under the influence of dressed magnetic potentials in the strong-field regime. We investigate the problem of adiabaticity of the rf dressing process and relate it to how close the dressed states are to degeneracy. Finally, we measure the lifetime of the rf dressed BECs and identify a rf-assisted two-body loss process induced by dipole-dipole interactions.

arXiv:0808.3931Physical Review ANov 20, 200817 citations

100\phantom{\rule{0.3em}{0ex}}\mathrm{mG}

. This is demonstrated by analyzing the trajectories of the atoms under the influence of dressed magnetic potentials in the strong-field regime. We investigate the problem of adiabaticity of the rf dressing process and relate it to how close the dressed states are to degeneracy. Finally, we measure the lifetime of the rf dressed BECs and identify a rf-assisted two-body loss process induced by dipole-dipole interactions.