Prototype 'optics table on a chip' places microwave photon in two colors at once

Jul 07, 2011
NIST's "optics table on a chip" is a superconducting circuit on a square sapphire chip about 6 millimeters wide. Scientists use the chip to place a single microwave photon in two frequencies, or colors, at the same time. The photon is prepared by an "artificial atom" (small yellow square) in the middle of the chip. The arrow shape at the lower left connects to a transmission line used to tune the SQUID (small black area near the point of the arrow). The SQUID couples together two resonant frequencies of the cavity (meandering line), and the photon oscillates between different superpositions of those frequencies. Credit: D. Schmidt/NIST

(PhysOrg.com) -- Researchers at the National Institute of Standards and Technology (NIST) have created a tunable superconducting circuit on a chip that can place a single microwave photon (particle of light) in two frequencies, or colors, at the same time.

This curious "superposition," a hallmark of the , is a chip-scale, microwave version of a common optics experiment in which a device called a sends a photon into either of two possible paths across a table of lasers, lenses and mirrors. The new NIST circuit can be used to create and manipulate different quantum states, and is thus a prototype of the scientific community's long-sought "optics table on a chip."

Described in , the NIST experiments also created the first microwave-based bit for linear optical . This type of quantum computer is typically envisioned as storing information in either the path of a or the polarization (orientation) of single photons. In contrast, a microwave version would store information in a photon's frequency. Quantum computers, if they can be built, could solve certain problems that are intractable today.

The new NIST circuit combines components used in superconducting experiments—a single photon source, a cavity that naturally resonates or vibrates at particular frequencies, and a coupling device called a SQUID (superconducting quantum interference device). Scientists tuned the SQUID properties to couple together two resonant frequencies of the cavity and then manipulated a photon to make it oscillate between different superpositions of the two frequencies. For instance, the photon could switch back and forth from equal 50/50 proportions of both frequencies to an uneven 75/25 split. This experimental setup traps photons in a "box" (the cavity) instead of sending them flying across an optical table.

"This is a new way to manipulate microwave quantum states trapped in a box," says NIST physicist José Aumentado, a co-author of the new paper. "The reason this is exciting is it's already technically feasible to produce interesting quantum states in chip-scale devices such as superconducting resonators, and now we can manipulate these states just as in traditional optics setups."

NIST researchers can control how the new circuit couples different quantum states of the resonator over time. As a result, they can create sequences of interactions to make simple optical circuits and reproduce traditional optics experiments. For example, they can make a measurement tool called an interferometer based on the frequency/color of a single photon, or produce special quantum states of light such as "squeezed" light.

Explore further: Study details laser pulse effects on behavior of electrons

More information: E. Zakka-Bajjani, F. Nguyen, M. Lee, L.R. Vale, R.W. Simmonds and J. Aumentado. Quantum superposition of a single microwave photon in two different 'colour' states. Nature Physics. Posted online July 3, 2011.

Related Stories

Yale scientists bring quantum optics to a microchip

Sep 08, 2004

A report in the journal Nature describes the first experiment in which a single photon is coherently coupled to a single superconducting qubit (quantum bit or "artificial atom"). This represents a new paradigm in which ...

NIST researchers create 'quantum cats' made of light

Sep 01, 2010

Researchers at the National Institute of Standards and Technology have created "quantum cats" made of photons (particles of light), boosting prospects for manipulating light in new ways to enhance precision ...

Scientists say it's high 'NOON' for microwave photons

Feb 15, 2011

An important milestone toward the realization of a large-scale quantum computer, and further demonstration of a new level of the quantum control of light, were accomplished by a team of scientists at UC Santa ...

Recommended for you

Particles, waves and ants

19 hours ago

Animals looking for food or light waves moving through turbid media – astonishing similarities have now been found between completely different phenomena.

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

gwrede
5 / 5 (1) Jul 07, 2011
Please, give me a source of these "two-color" photons, and a lab! I promise to not sleep or eat for weeks! Pretty please!!
denfire
not rated yet Jul 07, 2011
@gwrede: look up the paper in NATURE PHYSICS. It will provide the institute and ppl who preformed the experiment.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.