174 research outputs found
Measuring the local gravitational field using survival resonances in a dissipatively driven atom-optics system
We do a proof-of-principle demonstration of an atomic gravimeter based on survival resonances of dissipatively driven atoms. Exposing laser-cooled atoms to a sequence of near-resonant standing-wave light pulses reveals survival resonances when the standing-wave interference pattern accelerates. The resonant accelerations determine the local gravitational acceleration and we achieve a precision of 5 ppm with a drop distance less than 1 mm. The incisiveness of the resonances scales with the square of the drop time. Present results indicate that an appropriately designed atomic gravimeter based on survival resonances might be able to reach a precision of 1ÎĽGal with a 10-cm-high fountain. The relatively simple experimental construction of this technique may be of interest for a compact absolute atomic gravimeter
Distributed quantum sensing in a continuous variable entangled network
Networking plays a ubiquitous role in quantum technology. It is an integral
part of quantum communication and has significant potential for upscaling
quantum computer technologies that are otherwise not scalable. Recently, it was
realized that sensing of multiple spatially distributed parameters may also
benefit from an entangled quantum network. Here we experimentally demonstrate
how sensing of an averaged phase shift among four distributed nodes benefits
from an entangled quantum network. Using a four-mode entangled continuous
variable (CV) state, we demonstrate deterministic quantum phase sensing with a
precision beyond what is attainable with separable probes. The techniques
behind this result can have direct applications in a number of primitives
ranging from biological imaging to quantum networks of atomic clocks
Fiber coupled EPR-state generation using a single temporally multiplexed squeezed light source
A prerequisite for universal quantum computation and other large-scale
quantum information processors is the careful preparation of quantum states in
massive numbers or of massive dimension. For continuous variable approaches to
quantum information processing (QIP), squeezed states are the natural quantum
resources, but most demonstrations have been based on a limited number of
squeezed states due to the experimental complexity in up-scaling. The number of
physical resources can however be significantly reduced by employing the
technique of temporal multiplexing. Here, we demonstrate an application to
continuous variable QIP of temporal multiplexing in fiber: Using just a single
source of squeezed states in combination with active optical switching and a
200 m fiber delay line, we generate fiber-coupled Einstein-Podolsky-Rosen
entangled quantum states. Our demonstration is a critical enabler for the
construction of an in-fiber, all-purpose quantum information processor based on
a single or few squeezed state quantum resources
Deterministic generation of a two-dimensional cluster state
Measurement-based quantum computation offers exponential computational
speed-up via simple measurements on a large entangled cluster state. We propose
and demonstrate a scalable scheme for the generation of photonic cluster states
suitable for universal measurement-based quantum computation. We exploit
temporal multiplexing of squeezed light modes, delay loops, and beam-splitter
transformations to deterministically generate a cylindrical cluster state with
a two-dimensional (2D) topological structure as required for universal quantum
information processing. The generated state consists of more than 30000
entangled modes arranged in a cylindrical lattice with 24 modes on the
circumference, defining the input register, and a length of 1250 modes,
defining the computation depth. Our demonstrated source of 2D cluster states
can be combined with quantum error correction to enable fault-tolerant quantum
computation
Suppression of inhomogeneous broadening in rf spectroscopy of optically trapped atoms
We present a novel method for reducing the inhomogeneous frequency broadening
in the hyperfine splitting of the ground state of optically trapped atoms. This
reduction is achieved by the addition of a weak light field, spatially
mode-matched with the trapping field and whose frequency is tuned in-between
the two hyperfine levels. We experimentally demonstrate the new scheme with Rb
85 atoms, and report a 50-fold narrowing of the rf spectrum
- …