#### Quantum Nature of Light and Matter

to explore fundamental aspects of the quantum nature of light and its interaction with quantum matter and to develop applications relating to metrology and other areas of NIST’s mission, including measurement at and beyond the standard quantum limits.

INTENDED OUTCOME AND BACKGROUND

This topic area focuses on non-classical states of light and analogous states of matter. We study these quantum features in situations that range from the generation of quantum light in atomic vapors and in condensed matter systems, to the behavior of mechanical oscillators at the quantum level, to the impact of quantum light on quantum degenerate atomic gases. The latter part of the 20th century saw both the recognition of and production of radiation that cannot be produced by the motion of classical charges and currents. Squeezed light, single photons, and Fock or number states of light are among the non-classical phenomena that were realized, while remaining experimentally challenging. Some of these phenomena allowed optical measurement with precision below standard quantum uncertainties like the shot-noise limit, while others enabled non-intuitive phenomena like the violation of Bell’s inequalities.

Today NIST is a leader in developing this kind of non-classicality for metrology and other practical applications, and in extending such quantum behavior to new physical platforms. We have developed four-wave-mixing (4WM) in atomic vapor as a viable technique for creating bright, spatially multi-mode pairs of light beams with high relative intensity squeezing. We have developed quantum dots as reliable sources of single photons and have developed the tools to entangle the photons from such dots. We are creating micromechanical devices whose mechanical vibration can approach the quantum ground state, opening the way to applying the concepts of non-classicality in a radically new physical system. And we are using atomic-gas Bose-Einstein condensates, the atom-wave analogs of laser light, as a target for imprinting the non-classical character of light onto a macroscopic quantum atomic gas.

Our goals include: evaluating quantum light, atoms, and fabricated micromechanical systems for metrology beyond the standard quantum limits; the development of quantum information transfer between different physical qubit platforms according to which ones are most appropriate for a given function; and the fundamental study of quantum phenomena such as measurement and the quantum-classical interface.

**Highlights and Accomplishments**

**Press Releases**

Simply Weird Stuff: Making Supersolids with Ultracold Gas Atoms

Cross-Dressing Rubidium May Reveal Clues for Exotic Computing

Physicists Find Way to Control Individual Bits in Quantum Computers

Controlling Individual Qubits

Topological Insulator

Entangled Images and Delayed EPR Entanglement

Quantum Entangled Images Mix and Squeeze

Twin Beams for Quantum Imaging

Stunt Doubles Ultracold Atoms Could Replicate the Electron Jitterbug

Thousands of Atoms Swap Spins with Partners in Quantum Square Dance