Twin Matter Waves for Interferometry Beyond the Classical Limit

Abstract

Interferometers with atomic ensembles are an integral part of modern precision metrology. However, these interferometers are fundamentally restricted by the shot noise limit, which can only be overcome by creating quantum entanglement among the atoms. We used spin dynamics in Bose-Einstein condensates to create large ensembles of up to 10(4) pair-correlated atoms with an interferometric sensitivity -1.61(-1.1)(+0.98) decibels beyond the shot noise limit. Our proof-of-principle results point the way toward a new generation of atom interferometers.

Non-equilibrium dynamics of an unstable quantum pendulum explored in a spin-1 Bose–Einstein condensate

“…In particular, observation of coherent spin oscillations have confirmed the mean-field pendulum model for small condensates 4,9,10 . Spin evolution has been previously observed from metastable spin states in many experiments 6,8,[13][14][15][16][17] , however, the experiments have not yet demonstrated spin dynamic in agreement with quantum calculations, except in the perturbative, low-depletion limit at very short times (where a Bogoliubov expansion around the mean field can be used) 12,13,17 , or for conditions where the mean-field approach suffices. Here, we are able to observe quantum spin dynamics that agree well with quantum calculations and demonstrate a rich array of non-Gaussian fluctuations.…”

“…The equilibrium states, domain formation and spin dynamics of spinor condensates have been studied in many experiments [6][7][8][9][10][11][12][13][14][15][16][17] . In particular, observation of coherent spin oscillations have confirmed the mean-field pendulum model for small condensates 4,9,10 .…”

Atom interferometer in a double-well potential

“…Note that when the two modes represent atomic internal degrees of freedom, the beam-splitters can be realized by applying a precisely crafted rf-pulse [8,9,13]. 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.…”

“…Recently, the spin-squeezing has been generated in two-mode quantum systems [6][7][8][9][10][11][12]. A similar technique to detect the nonclassical correlations was used in a collection of atoms scattered from a single Bose-Einstein condensate in the spin-changing collisions [13].…”

Information-Recycling Beam Splitters for Quantum Enhanced Atom Interferometry

“…However, both of these experiments use only a small number of atoms (200-1200 atoms), so the absolute sensitivity of the device is low. Recently, correlated pairs of atoms generated from atomic spin-exchange collisions have been used to perform interferometry below the SQL [14]. The number of pair-correlated atoms used in the interferometer was approximately 8000, about 1=4 of the total available atoms in the experiment.…”