‘Entangling’ microscopic drum beats with electrical signals

Scientists at the US National Institute of Standards and Technology (NIST) have gotten closer to extending observations pf quantum entanglement into the macroscale (real life scale) according to an Oct. 3, 2013 news item on Nanowerk,

Extending evidence of quantum behavior farther into the large-scale world of everyday life, physicists at the National Institute of Standards and Technology (NIST) have “entangled” — linked the properties of — a microscopic mechanical drum with electrical signals. The results confirm that NIST’s micro-drum could be used as a quantum memory in future quantum computers, which would harness the rules of quantum physics to solve important problems that are intractable today. The work also marks the first-ever entanglement of a macroscopic oscillator, expanding the range of practical uses of the drum.

The Oct. 3, 2013 NIST news release, which originated the news item, describes how scientists are increasingly observing  and testing for entanglement at larger scales,

Entanglement is a curious feature of the quantum world once believed to occur only at atomic and smaller scales. In recent years, scientists have been finding it in larger systems. Entanglement has technological uses. For instance, it is essential for quantum computing operations such as correcting errors, and for quantum teleportation of data from one place to another.

The experiments, described Oct. 3, 2013, in Science Express,* were performed at JILA, a joint institute of NIST and the University of Colorado Boulder.

NIST introduced the aluminum micro-drum in 2011 and earlier this year suggested it might be able to store data in quantum computers.** The drum—just 15 micrometers in diameter and 100 nanometers thick—features both mechanical properties (such as vibrations) and quantum properties (such as the ability to store and transfer individual quanta of energy).

The drum is part of an electromechanical circuit that can exchange certain quantum states between the waveform of a microwave pulse and vibration in the drum. In the latest JILA experiment, a microwave signal “cooled” the drum to a very low energy level, just one unit of vibration, in a way analogous to some laser-cooling techniques. Then another signal caused the drum’s motion to become entangled with a microwave pulse that emerged spontaneously in the system.

The drum stored the quantum information in the form of vibrational energy for at least 10 microseconds, long enough to be useful in experiments. Then the same type of microwave signal that cooled the drum was used to transfer the state stored in the drum to a second microwave pulse.

Researchers measured the properties of the two microwave pulses—specific points on the curves of the travelling waves—and found that the results were strongly correlated over 10,000 repetitions of the experiment. The evidence of quantum entanglement comes from the fact that measuring the first microwave pulse allowed scientists to anticipate the characteristics of the second pulse with greater accuracy than would otherwise be expected. The correlations between the two pulses indicated that the first pulse was entangled with the drum and the second pulse encoded the drum’s quantum state.

The results suggest that the drum, in addition to its potential as a quantum memory device, also could be used to generate entanglement in microwaves, to convert one form of quantum information to an otherwise incompatible form, and to sense tiny forces with improved precision.

Here are two links to and citations for the researchers’ paper and for an article, respectively,,

* T.A. Palomaki, J.D. Teufel, R.W. Simmonds and K.W. Lehnert. Entangling mechanical motion with microwave fields. Science Express. Oct. 3, 2013. Science DOI: 10.1126/science.1244563
** See 2013 NIST Tech Beat article, “NIST Mechanical Micro-Drum Used as Quantum Memory,” at http://www.nist.gov/pml/div689/drum-031313.cfm.

The Science Express paper is behind a paywall and the NIST Tech Beat article is not avallable due to the US government shutdown.

This ‘entanglement’ news reminds me Geraldo Barbosa’s challenge about seeing quantum entanglement in every day life featured in my Mar. 1, 2012 posting,

You can find Barbosa’s paper/challenge, Can humans see beyond intensity images? here. The abstract presents the challenge this way,

The human’s visual system detect intensity images. Quite interesting, detector systems have shown the existence of different kind of images. Among them, images obtained by two detectors (detector array or spatially scanning detector) capturing signals within short window times may reveal a “hidden” image not contained in either isolated detector: Information on this image depend on the two detectors simultaneously. In general, they are called “high-order” images because they may depend on more than two electric fields. Intensity images depend on the square of magnitude of the light’s electric field. Can the human visual sensory system perceive high-order images as well? This paper proposes a way to test this idea. A positive answer could give new insights on the “visual-conscience” machinery, opening a new sensory channel for humans. Applications could be devised, e.g., head position sensing, privacy in communications at visual ranges and many others.

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