NIST’s “Optic Table On A Chip” Prototype Manipulates Quantum States

A tunable integrated circuit on a small 6 mm×6mm sapphire chip that can place a single photon in two frequencies simultaneously! Yes, this is the latest from the labs of the National Institute of Standards and Technology (NIST). The prototype circuit was developed by the NIST scientists to manipulate the different quantum states. This superconducting circuit is capable of placing a microwave photon in two colors/frequency ranges at the same time thus making it juggle between the different superpositions of those frequencies. This sounds insane, but oscillating between two different states or superposition is a well established and unique feature of the quantum physics. Actually, this optic table on the chip is the first of its kind prototype and the scientists had to wait for a sufficiently long time for it.

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The 6mm prototype chip makes a photon to exist in two quantum states simultaneously

This new chip is nothing but a nano scale microwave implementation of the relatively common beam splitter that is widely used in optics labs. If you look at the magnified picture of the chip given alongside, there is a small yellow square (called the artificial atom) in the centre of the chip and it is here that the photon is prepared. On the bottom left hand corner of the chip there is an arrow shaped sign and it actually is a link between the transmission line and the superconducting quantum interfering device (SQUID). The transmission line tunes the SQUID which then couples two different resonant frequencies of the resonant cavity (the central line). As a result, the placed microwave photon alternates between the two quantum states.

The research was published in the form of a paper in the journal Nature Physics. Besides this quantum stage change, the NIST team also devised the novel microwave based bit that will be used in linear optic quantum computing applications. The optic quantum computer is not a physical device and till now it exists only theoretically. It is supposed to store loads of information when kept in the path of the light beam or in the direction of polarization angle of single photons. The microwave optical quantum computer will have a slightly different modus operandi as it will store information in frequency of the photon. Scientists believe that the quantum computers that will utilize qubits or quantum numbers can solve very complex problems that are impossible to solve for the present day machines.

This super chip from NIST has everything that’s needed for superconducting quantum computing. It has a single photon source, a naturally resonating cavity that vibrates at particular frequencies, superconducting coupler in the form of SQUID, etc. The interesting fact is that the NIST scientists can control the way in which the circuit can couple the different quantum stages in a given period. Hence it can be used in the conventional optics related experiments also when it’s not busy in quantum computing.

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