Tiny graphene drum could form future quantum memory

August 28, 2014
Credit: Delft University of Technology

Scientists from TU Delft's Kavli Institute of Nanoscience have demonstrated that they can detect extremely small changes in position and forces on very small drums of graphene. Graphene drums have great potential to be used as sensors in devices such as mobile phones. Using their unique mechanical properties, these drums could also act as memory chips in a quantum computer. The researchers present their findings in an article in the August 24th edition of Nature Nanotechnology. The research was funded by the FOM Foundation, the EU Marie-Curie program, and NWO.

Graphene is famous for its special electrical properties, but research on the one-layer thin graphite was recently expanded to explore graphene as a mechanical object. Thanks to their extreme low mass, tiny sheets of graphene can be used the same was as the drumhead of a musician. In the experiment, scientists use microwave-frequency light to 'play' the graphene drums, to listen to its 'nano sound', and to explore the way graphene in these drums moves.

Dr. Vibhor Singh and his colleagues did this by using a 2D crystal membrane as a mirror in an 'optomechanical cavity'. "In optomechanics you use the interference pattern of light to detect tiny changes in the position of an object. In this experiment, we shot at a tiny graphene drum. The drum acts as a mirror: by looking at the interference of the microwave photons bouncing off of the drum, we are able to sense minute changes in the position of the graphene sheet of only 17 femtometers, nearly 1/10000th of the diameter of an atom.", Singh explains.

The microwave 'light' in the experiment is not only good for detecting the position of the drum, but can also push on the drum with a force. This force from light is extremely small, but the small mass of the and the tiny displacements they can detect mean that the scientist can use these forces to 'beat the drum': the scientists can shake the graphene drum with the momentum of light. Using this radiation pressure, they made an amplifier in which microwave signals, such as those in your mobile phone, are amplified by the mechanical motion of the drum.

The video will load shortly

The scientists also show you can use these drums as 'memory chips' for microwave photons, converting photons into mechanical vibrations and storing them for up to 10 milliseconds. Although that is not long by human standards, it is a long time for a computer chip. "One of the long-term goals of the project is explore 2D crystal drums to study quantum motion. If you hit a classical drum with a stick, the drumhead will start oscillating, shaking up and down. With a quantum drum, however, you can not only make the drumhead move up and then down, but also make it into a 'quantum superposition', in which the drum head is both moving up and moving down at the same time ", says research group leader Dr. Gary Steele. "This 'strange' quantum motion is not only of scientific relevance, but also could have very practical applications in a quantum computer as a quantum 'memory chip'".

In a quantum computer, the fact that quantum 'bits' that can be both in the state 0 and 1 at the same time allow it to potentially perform computations much faster than a classical computer like those used today. Quantum graphene drums that are 'shaking up and down at the same time' could be used to store quantum information in the same way as RAM chips in your computer, allowing you to store your quantum computation result and retrieve it at a later time by listening to its quantum sound.

Explore further: Physicists 'entangle' microscopic drum's beat with electrical signals

More information: "Optomechanical coupling between a multilayer graphene mechanical resonator and a superconducting microwave cavity", Nature Nanotechnology 24 August 2014. www.nature.com/nnano/journal/vaop/ncurrent/full/nnano.2014.168.html

Related Stories

Physicists use mechanical micro-drum used as quantum memory

March 13, 2013

JILA researchers demonstrated thatinformation encoded as a specific point in atraveling microwave signal—the vertical and horizontal positions of a wave pattern at a certain ime—can be transferred to the mechanical beat ...

Resonant energy transfer from quantum dots to graphene

May 22, 2014

Semiconductor quantum dots (QDs) are nanoscale semiconductors that exhibit size dependent physical properties. For example, the color (wavelength) of light that they absorb changes dramatically as the diameter decreases. ...

On the edge of graphene

August 11, 2014

Researchers at the National Physical Laboratory (NPL) have discovered that the conductivity at the edges of graphene devices is different to the central material.

Recommended for you

A levitated nanosphere as an ultra-sensitive sensor

June 28, 2017

Sensitive sensors must be isolated from their environment as much as possible to avoid disturbances. Scientists at ETH Zurich have now demonstrated how to remove from and add elementary charges to a nanosphere that can be ...

Ruthenium rules for new fuel cells

June 28, 2017

Rice University scientists have fabricated a durable catalyst for high-performance fuel cells by attaching single ruthenium atoms to graphene.

Researchers create very small sensor using 'white graphene'

June 28, 2017

Researchers from TU Delft in The Netherlands, in collaboration with a team at the University of Cambridge (U.K.), have found a way to create and clean tiny mechanical sensors in a scalable manner. They created these sensors ...


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.