Experiment Looks to Bridge Classical Physics and Quantum Mechanics

Researchers takes steps to observe the ghostly effects of quantum mechanics in objects larger than atoms

Qubit Madness

Tiny nanoscale structures may move like atoms do on a quantum mechanics scale.Pierre Echternach (JPL) and Matt LaHaye (Caltech)

Pity the science students who can't just learn about Newtonian laws of physics and falling objects. No, there's also the small-scale world of quantum physics where atoms can exist in two states at once, or remain connected across millions of light years. But researchers may have found relief in a potentially groundbreaking experiment that could demonstrate quantum mechanics in large objects. It's not just for atoms!

Quantum mechanics operates in a bizarro world that includes superposition, where atoms can maintain more than one state at a time. Matter can also become entangled so that it remains connected across vast distances -- a ghostly phenomenon dubbed "spooky action at a distance" by Albert Einstein.

"It'd be weird to think of ordinary matter behaving in a quantum way, but there's no reason it shouldn't," said Keith Schwab, a physicist at Caltech who collaborated on the study that appeared in the journal Nature. "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 Caltech researchers wanted to see if objects larger than atoms could reflect such freaky physics. They built two nanoscale devices, including a tiny aluminum bridge that consists of 10 billion atoms and weighs 40 billionths of a milligram. The other device is a superconductor "qubit" which can exist in just two energy states, a ground state and an excited state.

Applying an electrical current to the bridge made it vibrate from side to side, and also made the nearby qubit jump between the two energy states. The overlapping electric fields from both objects allowed the researchers to see if they could figure out the energy state of the qubit from the bridge's vibrations, as helpfully explained by Seed Magazine. The readings of the bridge confirmed the hunch by reflecting the energy state of the qubit.

The next step involves flipping the experiment and trying to spot the bridge's energy state from looking at the qubit readings. Accomplishing such a feat would make the bridge the largest object yet to reflect quantum mechanics. And that's when things get crazy, because the researchers plan to go on and examine whether the bridge exists in two places at once.

There's only one thing to do in this situation -- grab your gun and bring in the cat.