Quantum Walk in Position Space with Single Optically Trapped Atoms

By M. Karski, L. Förster, Jai-Min Choi, Andreas Steffen, W. Alt, D. Meschede, A. Widera. Science, 2009

599 citations recorded by the source corpus.

Strolling Out on a Quantum Walk In a random walk, a walker moves one step to the left or one step to the right depending on the outcome of a coin toss. The distribution between possible locations is well known and forms the basis for algorithms in information processing, describing diffusion processes in physics or biology, and has even been used as a model for stock market prices. Karski et al. (p. 174) use a single caesium atom trapped in a one-dimensional optical lattice to implement the quantum counterpart—a quantum walk. The coherence of a quantum system results in a departure from the classical picture, producing a distribution that is quite different that depends on the internal state of the atom. The results may have implications for search algorithms and quantum information processing protocols. A single cesium atom trapped in an optical lattice is used to illustrate a quantum walk. The quantum walk is the quantum analog of the well-known random walk, which forms the basis for models and applications in many realms of science. Its properties are markedly different from the classical counterpart and might lead to extensive applications in quantum information science. In our experiment, we implemented a quantum walk on the line with single neutral atoms by deterministically delocalizing them over the sites of a one-dimensional spin-dependent optical lattice. With the use of site-resolved fluorescence imaging, the final wave function is characterized by local quantum state tomography, and its spatial coherence is demonstrated. Our system allows the observation of the quantum-to-classical transition and paves the way for applications, such as quantum cellular automata.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/b154f9a9ad6bfc095937d56e9dca5edac63c5e70

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Citations in the corpus

Universal Computation by Multiparticle Quantum Walk (2012, background): “cal system such that locality of the graph translates into locality of the Hamiltonian, but with substantial overhead that precludes the possibility of dramatic computational speedup (see for example [16, 20, 22]). While such experiments may serve as useful testbeds of presently available quantum in”
Exceptional topology of non-Hermitian systems (2019, unknown): “…by Aharonov, Davidovich, and Zagury (1993), and quantum walks have been realized in several experimental platforms, such as trapped atoms (Karski et al. , 2009), trapped ions (Schmitz et al. , 2009; Z¨ahringer et al. , 2010), optical fiber networks (Broome et al. , 2010; Schreiber et al.…”
Exploring topological phases with quantum walks (2010, methodology): “The one dimensional DTQW protocol employed in recent experiments[11–14] is depicted schematically in Fig.”
Quantum walks: a comprehensive review (2012, unknown): “have implemented a quantum walk on the line with single neutral atoms by delocalizing them over the sites of a one-dimensional spin-dependent optical lattice [219], Lavička et al.”
Anderson localization of entangled photons in an integrated quantum walk (2013, methodology): “quantum walks were performed with trapped atoms [25], ions [26, 27], energy levels in NMR schemes [28], photons in waveguide structures [29], in bulk optics [9, 30], and in a fiber loop configuration [10, 31, 32].”