Advances in Atomtronics

Abstract

Atomtronics is a relatively new subfield of atomic physics that aims to realize the device behavior of electronic components in ultracold atom-optical systems. The fact that these systems are coherent makes them particularly interesting since, in addition to current, one can impart quantum states onto the current carriers themselves or perhaps perform quantum computational operations on them. After reviewing the fundamental ideas of this subfield, we report on the theoretical and experimental progress made towards developing externally-driven and closed loop devices. The functionality and potential applications for these atom analogs to electronic and spintronic systems is also discussed.

Keywords: Bose–Einstein condensates; atomtronics; open quantum systems; quantum sensing; quantum simulation.

Figure 1

Figure taken from Reference [10]. (a) An illustration of a traditional electronic p–n junction diode connected to an external power source. (b) The equivalent atomtronic circuit where an optical lattice with an external energy gap labeled ‘System’ is attached to two external optical lattice reservoirs, which drive neutral, ultracold atoms across the system by acting as a source (left) and sink (right). The external energy gap of the system is responsible for generating the diodelike response in the optical lattice.

Figure 2

Figure taken from [11]. An illustration of the system’s Fock states energies. The blue solid and red dashed arrows represent the action of the left and right reservoirs, respectively. (a) The energy schematic of the reverse bias dynamics of the two site atomtronic diode. Regardless of which state the system starts in, it evolves almost entirely to the $|02\rangle$ state. (b) The energy schematic of the forward-bias dynamics of the two-site atomtronic diode. The resonance between the $|20\rangle$ and $|11\rangle$ states, in combination with the action of the reservoir’s attempt to keep a population of two atoms on the left site while leaving the right site vacant, leads to the following two cycles of states that lead to current flow through the system: $|20\rangle \to |11\rangle \to |10\rangle \to |20\rangle$ and $|20\rangle \to |11\rangle \to |21\rangle \to |20\rangle$.

Figure 3

Figure taken from [14]. (a) A schematic of the optical dipole trap, (b) the geometry of the barrier beam, (c) experimental absorption image of the ring condensate with $\theta$ marking the arc of the barrier trajectory, and (d) experimental images of the barrier’s angular positions at integer multiples of ${60}^{\circ }$.