Demonstration of the Jaynes-Cummings ladder with Rydberg-dressed atoms

THIS PAPER WAS CHOSEN AS AN “EDITORS’ SUGGESTION” IN PHYSICAL REVIEW A, Vol. 95, Iss. 4 — April 2017.

Demonstration of the Jaynes-Cummings ladder with Rydberg-dressed atoms

Jongmin Lee, Michael J. Martin, Yuan-Yu Jau, Tyler Keating, Ivan H. Deutsch, and Grant Biedermann

The Jaynes-Cummings model, a widely employed theoretical framework in cavity quantum electrodynamics, is experimentally tested on a platform involving Rydberg-blockaded atomic ensembles. The work opens the way to a richer exploration of protocols for quantum control or, more broadly, quantum computing.

The full article is available online at Phys. Rev. A 95, 041801(R) (2017)

 

FIG 1.  Experimental setup.  The Rydberg laser and the Raman lasers are  aligned along the x axis.  Two optical tweezers are formed by two lasers  with an angular separation θ..  In this setup, eight electrodes control the electric fields near the trapped atoms.  The bias magnetic field is applied along the x axis.

 

 

Integrated quantum information processing in the dispersive regime with fewer atoms

Nanofiber Scheme
The integration of nanophotonics with ultracold atoms opens the door to new protocols in quantum information processing. Strong entangling interactions between atoms and photons are the key ingredient. Whereas a resonant interaction can lead to the strongest entanglement per atom, this requires special geometries that limit decoherence. Off-resonant dispersive interactions, where a phase shift is associated with the atom-photon interaction, provides an alternative route to strong entanglement. This can be achieved due to the “cooperativity” of a large ensemble of atoms that can be homogeneously trapped in the evanescent field of an optical nanofiber using well-known techniques (see figure above). The optical scattering cross section closely matches the guided beam mode area across the entire length of the nanofiber. Our recent paper pedagogically develops the theory to describe how the light dispersively responds to an ensemble of atoms in the optical nanofiber waveguide platform and how this can yield large cooperativity. As an application of the theory, we study the creation of spin squeezed states for application in improved precision of atomic clocks. With only a few thousand Cesium atoms, a nontrivial squeezed state can be created using an anisotropic property of the nanofiber modes, which is not available or hard to implement in free space. This is a first step towards more general protocols involving the production of nonGaussian atomic states and their interaction with nonclassical light.

 

Comments and discussions can go to its Github repository.

Reference:

Xiaodong Qi, Ben Q. Baragiola, Poul S. Jessen, and Ivan H. Deutsch, Dispersive response of atoms trapped near the surface of an optical nanofiber with applications to quantum nondemolition measurement and spin squeezing, Phys. Rev. A 93, 023817 (2016). [PDF]

“Quanta Magazine” Interviews Ivan Deutsch

Ivan Deutsch Q&A in "Quanta Magazine"

Ivan Deutsch Q&A in “Quanta Magazine”

 

The Ivan Deutsch group at CQuIC received a welcome surprise with the publication of an interview with Dr. Deutsch in “Quanta Magazine“. The Deutsch group’s research has focused on the control of a 16 dimensional quantum system, or “qudit” in the quantum information parlance. This system offers the opportunity to study robust quantum control techniques (where errors introduced in the control protocols do not introduce too many errors into the behavior of the system), as well as the opportunity to examine novel quantum effects.