Quantum Physics' Big News: Weird Quantum State Observed in the Largest Object Yet

By Andrew Moseman | March 18, 2010 10:14 am

quantumresonatorOnly the tiny bits of matter, atoms and molecules, have even been observed in a quantum state—until now. In a study in this week’s Nature, physicists report that they’ve put the largest object ever into that state where the weird rules of quantum mechanics apply, and things can be in two places at once. Research leader Andrew Cleland says: “There is this question of where the dividing line is between the quantum world and the classical world we know. We know perfectly well that things are not in two places at the same time in our everyday experience, but this fundamental theory of physics says that they can be” [BBC News].

The researchers’ “quantum resonator,” seen here, is a vibrating device that measures only in micrometers, but that’s large enough for us to see it with a little help from a scanning electron microscope. To see quantum mechanics in action, scientists try to put an object into its ground state, the point when no more energy can be removed from the system. Then they add a quantum of energy back in, which can oscillate between locations. Although only one quantum of energy is put in, any measurements will show either zero or one quanta; strictly, the atom has both [BBC News].

Doing this, however, requires ultra-low temperatures near absolute zero. Unfortunately, the ground state temperature is related to the vibrational frequency. To reach it, you either need to reach temperatures below those possible with current refrigeration methods, or have something that can vibrate incredibly quickly [Ars Technica]. Unable to reach the 50 billionths of a degree Kelvin they thought would be necessary, the researchers went the other way. They crafted this device to vibrate at 6 billion times per second, which meant they could get by with slightly warmer temperature.

Once the system reached ground state, the team created a phonon, a minuscule unit of vibrating energy. And in aluminum nitride layered between two aluminum electrodes, the team observed quantum behavior—the system was in a superpostion of states, simultaneously having both zero and one quanta of energy.

Cleland’s find could be another step toward quantum computing. But for those more interested in mind puzzles than practicality, this line of research could test predictions about “Schrödinger cat” states — named for a hypothetical feline simultaneously alive and dead — in which a system exists in a mix of states known as a superposition. Cleland’s team showed, somewhat indirectly, that a form of superposition existed inside their resonator [Science News].

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Image: Andrew Cleland

  • chrisstevens

    Am I the only person to have experienced the state of superposition when I wake up after a heavy party in bed at home still feeling I am at the previous night’s festivities?
    Is this convincing evidence of Quantum Entanglement in ordinary matter at non-absolute zero temperatures?

  • Georg

    “…having both zero and one quanta of energy.”

    One quantum
    Two quanta

  • Jockaira


    This is not a spelling error. The word above, “quanta” is in a superposition of states. If you can blink your eyes fast enough you can also see the “um” state. Of course, as an observer you affect the spelling of the word, so the effort of your eyelids may not be sufficient to unentwine the state of the word because of your belief that the spelling is wrong.

    “I believe that it is better to be right half the time than wrong all the time. If I believe it then it must be true.”–Charles Daniel

  • Rich Langsford

    This is a fantastic event (events?), but being an illiterate at these nanoscopic dimensions, would be greatly appreciative if someone could explain just what we are seeing in the photo.
    What is the representation of the two states? Thanks!

  • http://www.perimeterinstitute.ca/Outreach/Quantum_Tamers/The_Quantum_Tamers/ John

    The findings are fueling conversations about objects seeming to appear in two places at the same time. The famous thought experiment known as Schrödinger’s Cat deals with the idea at an everyday level. There is an interesting visualization of this online at The Quantum Tamers site, along with clips on entanglement and other ideas from the quantum world.

    Some of the scientists from the program are interviewed on MSNBC’s Cosmic Log, http://cosmiclog.msnbc.msn.com/archive/2010/03/17/2231022.aspx.

    The clips are here at the Perimeter Institute site, a non-profit research and outreach organization dealing in areas of theoretical physics. http://www.perimeterinstitute.ca/Outreach/Quantum_Tamers/The_Quantum_Tamers/. This offers some food for thought when thinking about the quantum world and possible quantum technologies.

  • Phil

    Once we can “communicate” or control devices such as this we will be able to truly take advantage of the power of superpositions.

    I suspect ultra thin carbon could be the substrate used for building quantum dots and quantum dot manufacturing machines. Since we can use a flash of light to disassemble the carbon; in theory we would be left with quantum dots and nano-sized super-positioning machines capable of being controlled by the macro level.

  • Rowley

    Is zero a quantum of energy, then?

  • http://www.youtube.com/user/Zamolxx Serban Enache

    Papers written by Miles Mathis
    -Superposition http://milesmathis.com/super.html
    -Superposition again http://milesmathis.com/super2.html
    -Schrodinger’s cat http://milesmathis.com/cat.html


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