Quantum computing with Bose--Einstein condensate Bragg interferometry

上妻 幹男, Mikio Kozuma

Naceur Gaaloul

J. Küber, F. Schmaltz, G. Birkl

We present the experimental implementation of double Bragg diffraction of Bose-Einstein condensates (BECs) as proposed in [E. Giese, A. Roura, G. Tackmann, E. M. Rasel, and W. P. Schleich, Phys. Rev. A \textbf{88}, 053608 (2013)]. We excite Rabi oscillations between the three coupled momentum states $\left| 0 \hbar k \right\rangle$ and $\left| \pm 2 \hbar k \right\rangle$. By selecting appropriate interaction times we generate highly efficient beamsplitters and mirrors for Bose-Einstein condensates. In addition, we demonstrate higher-order double Bragg diffraction and display beamsplitters with up to $ \pm 6 \hbar k$ momentum transfer. We compare double Bragg diffraction to several other experimental realizations of beamsplitters. Finally, we show that double Bragg diffraction is well suited for matter wave interferometry by realizing a Ramsey-type interferometer in a quasi one-dimensional waveguide.

Matthias Gersemann, Martina Gebbe, Sven Abend +2 more

Abstract Out of a single Bose-Einstein condensate (BEC), we create two simultaneous interferometers, as employed for the differentiation between rotations and accelerations. Our method exploits the precise motion control of BECs combined with the precise momentum transfer by double Bragg diffraction for interferometry. In this way, the scheme avoids the complexity of two BEC sources and can be readily extended to a six-axis quantum inertial measurement unit. Graphical abstract

Martina Gebbe, Sven Abend, Matthias Gersemann +6 more

Robin Corgier, Luca Pezzè, Augusto Smerzi

We propose a scheme for trapped-atom interferometry using an interacting Bose-Einstein condensate. The condensate is controlled and spatially split into two confined external momentum modes through a series of Bragg pulses. The proposed scheme (i) allows the generation of large entanglement in a trapped-interferometer configuration via one-axis twisting dynamics induced by interatomic interaction and (ii) avoids the suppression of interactions during the interferometer sequence by a careful manipulation of the state before and after phase encoding. The interferometer can be used for the measurement of gravity with a sensitivity beyond the standard quantum limit.