At the quantum level, the atoms that make up matter and the photons that make up light behave in a number of seemingly bizarre ways. Particles can exist in "superposition," in more than one state at the same time (as long as we don't look), a situation that permitted Schrödinger's famed cat to be simultaneously alive and dead; matter can be "entangled"-Albert Einstein called it "spooky action at a distance"-such that one thing influences another thing, regardless of how far apart the two are.

Scanning electron micrograph of a superconducting qubit in close proximity to a nanomechanical resonator. The nanoresonator is the bilayer (silicon nitride/aluminum) beam spanning the length of the trench in the center of the image; the qubit is the aluminum island located to the left of the nanoresonator. An aluminum electrode, located adjacent to the nanoresonator on the right, is used to actuate and sense the nanoresonator's motion. [Credit: Electron beam lithography was performed by Richard Muller at JPL. Nanoresonator etch was performed by Junho Suh in the Roukes Lab. Image taken by Junho Suh.]

Previously, scientists have successfully measured entanglement and superposition in photons and in small collections of just a few atoms. But physicists have long wondered if larger collections of atoms-those that form objects with sizes closer to what we are familiar with in our day-to-day life-also exhibit quantum effects.

"Atoms and photons are intrinsically quantum mechanical, so it's no surprise if they behave in quantum mechanical ways. The question is, do these larger collections of atoms do this as well," says Matt LaHaye, a postdoctoral research scientist working in the laboratory of Michael L. Roukes, a professor of physics, applied physics, and bioengineering at the California Institute of Technology (Caltech) and codirector of Caltech's Kavli Nanoscience Institute.

"It'd be weird to think of ordinary matter behaving in a quantum way, but there's no reason it shouldn't," says Keith Schwab, an associate professor of applied physics at Caltech, and a collaborator of Roukes and LaHaye. "If single particles are quantum mechanical, then collections of particles should also be quantum mechanical. And if that's not the case-if the quantum mechanical behavior breaks down-that means there's some kind of new physics going on that we don't understand."

The tricky part, however is devising an experiment that can detect quantum mechanical behavior in such ordinary objects-without, for example, those effects being interfered with or even destroyed by the experiment itself.

Now, however, LaHaye, Schwab, Roukes,  and their colleagues have developed a new tool that meets such fastidious demands and that can be used to search for quantum effects in an ordinary object. The researchers describe their work in the latest issue of the journal Nature.

In their experiment, the Caltech scientists used microfabrication techniques to create a very tiny nanoelectromechanical system (NEMS) resonator, a silicon-nitride beam-just 2 micrometers long, 0.2 micrometers wide, and weighing 40 billionths of a milligram-that can resonate, or flex back and forth, at a high frequency when a voltage is applied.