Resonant wavepackets and shock waves in an atomtronic SQUID

Wang, Yi-Hsieh; Kumar, Avinash; Jendrzejewski, Fred; Wilson, Ryan; Edwards, Mark; Eckel, Stephen; Campbell, Gretchen K.; Clark, Charles W.

doi:10.1088/1367-2630/17/12/125012

Cited by 34 publications

(27 citation statements)

References 55 publications

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“…For an infinite one-dimensional channel, for example, the flow is not quantized. However, two equal but oppositely directed phonon wavepackets (similar to those generated in [25]) traveling in the channel will move with different velocities in the presence of a background flow. The use of a ring allows for a straightforward means of detecting the frequency shift: precession of a phonon standingwave mode.…”

Section: Theorymentioning

confidence: 99%

Minimally destructive, Doppler measurement of a quantized flow in a ring-shaped Bose–Einstein condensate

et al. 2016

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The Doppler effect, the shift in the frequency of sound due to motion, is present in both classical gases and quantum superfluids. Here, we perform an insitu, minimally destructive measurement, of the persistent current in a ring-shaped, superfluid Bose-Einstein condensate using the Doppler effect. Phonon modes generated in this condensate have their frequencies Doppler shifted by a persistent current. This frequency shift will cause a standing-wave phonon mode to be "dragged" along with the persistent current. By measuring this precession, one can extract the background flow velocity. This technique will find utility in experiments where the winding number is important, such as in emerging 'atomtronic' devices.

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Section: Theorymentioning

confidence: 99%

Minimally destructive, Doppler measurement of a quantized flow in a ring-shaped Bose–Einstein condensate

et al. 2016

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“…These atomic species have, however, the drawback that they typically form BECs with a low number of particles, which limits the sensitivity to magnetic fields. Although it is outside of the scope of this paper to give accurate values of the sensitivities that could be achieved with this apparatus, making use of equations (13) and (14), and considering the experimental parameters reported in [48], we have estimated that, in principle, this magnetometer would allow to measure changes in the magnetic field on the order of a few pT at a bandwidth of 1 Hz.…”

Section: Sensing Of Magnetic Fieldsmentioning

confidence: 99%

Quantum sensing using imbalanced counter-rotating Bose–Einstein condensate modes

2018

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A quantum device for measuring two-body interactions, scalar magnetic fields and rotations is proposed using a Bose-Einstein condensate (BEC) in a ring trap. We consider an imbalanced superposition of orbital angular momentum modes with opposite winding numbers for which a rotating minimal atomic density line appears. We derive an analytical model relating the angular frequency of the minimal density line rotation to the strength of the nonlinear atom-atom interactions and the difference between the populations of the counter-propagating modes. Additionally, we propose a full experimental protocol based on direct fluorescence imaging of the BEC that allows to measure all the quantities involved in the analytical model and use the system for sensing purposes.In this article, we propose to use a BEC trapped in a two-dimensional (2D) ring potential for measuring with high sensitivity nonlinear interactions, scalar magnetic fields and rotations. We consider an imbalanced superposition of counter-rotating orbital angular momentum (OAM) modes, whose spatial density distribution presents a minimal line. A weak two-body interaction between the atoms of the BEC leads to a rotation of the minimal atomic density line whose angular frequency is directly related to the strength of such interactions. This phenomenon is somehow reminiscent of the propagation of gray solitons, which originate in repulsively interacting BECs due to a compensation between the kinetic and mean field interaction energies. In this case, however, the minimal density line appears for attractive, repulsive or even non-interacting BECs, and is a consequence of the interference between the counter-propagating modes that takes place due to the circular geometry of the system.The rest of the paper is organized as follows. In section 2 we describe the physical system and we derive an analytical expression that accounts for the rotation of the line of minimal density. In section 3, we take profit of this expression to propose a full experimental protocol to measure the interaction strength, which is proportional to the s-wave scattering length. Far from the resonant field or with a dilute enough BEC, the relation between the scattering length and the applied magnetic field given by Feshbach resonances could be exploited to use the system as a novel type of scalar magnetometer. We also outline the possibility of using the system as a rotation sensor. Finally, in section 4 we summarize the main conclusions. In appendix A we derive the general equations that govern the dynamics of a BEC carrying OAM in a ring potential, and in appendix B we give further details about the experimental implementation of the measurement protocol.

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“…Those new techniques also provide opportunities for testing and verifying theories of transport properties in solid state devices and cold atom systems56789101112. Recently, the concept of atomtronics13141516 has drawn intense attention due to intriguing experimental and theoretical studies, including quantum point contact1718, atomic SQUID1920212223, transistor24, capacitor25, and open quantum systems26272829. There is a bright future for atomtronics, and here we will address a challenging issue on driving atoms in atomtronic circuits via local manipulations.…”

mentioning

confidence: 99%

Challenges and constraints of dynamically emerged source and sink in atomtronic circuits: From closed-system to open-system approaches

Lai

Chien

2016

Sci Rep

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While batteries offer electronic source and sink for electronic devices, atomic analogues of source and sink and their theoretical descriptions have been a challenge in cold-atom systems. Here we consider dynamically emerged local potentials as controllable source and sink for bosonic atoms. Although a sink potential can collect bosons in equilibrium and indicate its usefulness in the adiabatic limit, sudden switching of the potential exhibits low effectiveness in pushing bosons into it. This is due to conservation of energy and particle in isolated systems such as cold atoms. By varying the potential depth and interaction strength, the systems can further exhibit averse response, where a deeper emerged potential attracts less bosonic atoms into it. To explore possibilities for improving the effectiveness, we investigate what types of system-environment coupling can help bring bosons into a dynamically emerged sink, and a Lindblad operator corresponding to local cooling is found to serve the purpose.

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Resonant wavepackets and shock waves in an atomtronic SQUID

Cited by 34 publications

References 55 publications

Minimally destructive, Doppler measurement of a quantized flow in a ring-shaped Bose–Einstein condensate

Minimally destructive, Doppler measurement of a quantized flow in a ring-shaped Bose–Einstein condensate

Quantum sensing using imbalanced counter-rotating Bose–Einstein condensate modes

Challenges and constraints of dynamically emerged source and sink in atomtronic circuits: From closed-system to open-system approaches

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