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A quantum random walk of a Bose-Einstein condensate in momentum space
  • Gil Summy,
  • Sandro Wimberger
Sandro Wimberger
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Abstract

Each step in a quantum random walk is typically understood to have two basic components; a ‘coin-toss’ which produces a random superposition of two states, and a displacement which moves each component of the superposition by different amounts. Here we suggest the realization of a walk in momentum space with a spinor Bose-Einstein condensate subject to a quantum ratchet realized with a pulsed, off-resonant optical lattice. By an appropriate choice of the lattice detuning, we show how the atomic momentum can be entangled with the internal spin states of the atoms. For the coin-toss, we propose to use a microwave pulse to mix these internal states. We present the first experimental results showing a new type of ratchet, and through a series of simulations, demonstrate how our proposal can allow for extraordinary control of the quantum walk. This should allow for the investigation of possible biases, and classical-to-quantum dynamics in the presence of natural and engineered noise.