Coherent manipulation of Bose–Einstein condensates with state-dependent microwave potentials on an atom chip

Abstract

Entanglement-based technologies, such as quantum information processing, quantum simulations, and quantum-enhanced metrology, have the potential to revolutionise our way of computing and measuring and help clarifying the puzzling concept of entanglement itself. Ultracold atoms on atom chips are attractive for their implementation, as they provide control over quantum systems in compact, robust, and scalable setups. An important tool in this system is a potential depending on the internal atomic state. Coherent dynamics in this potential combined with collisional interactions allows entanglement generation both for individual atoms and ensembles. Here, we demonstrate coherent manipulation of Bose-condensed atoms in such a potential, generated in a novel way with microwave near-fields on an atom chip. We reversibly entangle atomic internal and motional states, realizing a trapped-atom interferometer with internal-state labelling. Our system provides control over collisions in mesoscopic condensates, paving the way for on-chip generation of many-particle entanglement and quantum-enhanced metrology with spin-squeezed states.

Macroscopic quantum information processing using spin coherent states

“…[11,12]. Here we discuss an alternative all-optical method for single qubit rotations which naturally fits into the scheme for two qubit rotations (discussed below) [31].…”

Atom interferometer in a double-well potential

“…Again, there is a close analogy between this expression and the bound (27). As in the case of (27), the sensitivity (44) drops below the SNL, if the input state is phasesqueezed (ξ 2 φ < 1).…”

“…As in the case of (27), the sensitivity (44) drops below the SNL, if the input state is phasesqueezed (ξ 2 φ < 1). Note, however, that the presence of ǫ in the denominator deteriorates the precision.…”

“…However, when the modes are spatially separated, as in a double-well potential [12,[24][25][26][27], the beam-splitter is more difficult to implement. In an alternative scenario of obtaining the interferometric signal from the evolution (10), the gas is simply released from the trap.…”

Splitting dynamics of a two-species Bose-Einstein condensate in two translating traps

“…This requires precise control over guiding and transporting atoms. Atomic chips provides a playground for achieving this task due to their tunability over a micron-size structure [18][19][20][21][22][23][24][25][26][27][28][29][30]. The combination of laser cooling and chip-scale device fabrication may find interesting applications in areas such as quantum metrology and quantum computation.…”