Making big 'Schroedinger cats': Quantum research pushes boundary by testing micro theory for macro objects

Jul 21, 2013

Since Erwin Schroedinger's famous 1935 cat thought experiment, physicists around the globe have tried to create large scale systems to test how the rules of quantum mechanics apply to everyday objects.

Researchers at the University of Calgary recently made a significant step forward in this direction by creating a large system that is in two substantially different states at the same time. Until this point, scientists had only managed to recreate on much smaller scales.

Professor Alex Lvovsky and associate professor Christoph Simon from the Physics and Astronomy department together with their graduate students revealed their findings in a world leading physics research journal, Nature Physics.

Understanding Schroedinger's cat

In contrast to our everyday experience, allows for particles to be in two states at the same time – so-called . A radioactive nucleus, for example, can simultaneously be in a decayed and non-decayed state.

Applying these quantum rules to large objects leads to paradoxical and even bizarre consequences. To emphasize this, Erwin Schroedinger, one of the founding fathers of quantum physics, proposed in 1935 a thought experiment involving a cat that could be killed by a mechanism triggered by the decay of a single . If the nucleus is in a superposition of decayed and non-decayed states, and if quantum physics applies to large objects, the belief is that the cat will be simultaneously dead and alive.

While with properties akin to 'Schroedinger's cat' have been achieved at a micro level, the application of this principle to everyday macro objects has proved to be difficult to demonstrate.

"This is because large are extremely fragile and tend to disintegrate when subjected to any interaction with the environment," explains Lvovsky.

Photons help to illuminate the paradox

The breakthrough achieved by Calgary quantum physicists is that they were able to contrive a quantum state of light that consists of a hundred million light quanta (photons) and can even be seen by the naked eye. In their state, the "dead" and "alive" components of the "cat" correspond to quantum states that differ by tens of thousands of photons.

"The laws of which govern the microscopic world are very different from classical physics that rules over large objects such as live beings," explains lead author Lvovsky. "The challenge is to understand where to draw the line and explore whether such a line exists at all. Those are the questions our experiment sheds light on," he states.

While the findings are promising, study co-author Simon admits that many questions remain unanswered.

"We are still very far from being able to do this with a real cat," he says. "But this result suggests there is ample opportunity for progress in that direction."

Explore further: When parallel worlds collide, quantum mechanics is born

More information: Nature Physics DOI: 10.1038/nphys2682

Related Stories

Quantum cats are hard to see

Dec 16, 2011

Are there parallel universes? And how will we know? This is one of many fascinations people hold about quantum physics. Researchers from the universities of Calgary and Waterloo in Canada and the University ...

New principle may help explain why nature is quantum

May 14, 2013

Like small children, scientists are always asking the question 'why?'. One question they've yet to answer is why nature picked quantum physics, in all its weird glory, as a sensible way to behave. Researchers ...

Recommended for you

Quantum holograms as atomic scale memory keepsake

Oct 21, 2014

Russian scientists have developed a theoretical model of quantum memory for light, adapting the concept of a hologram to a quantum system. These findings from Anton Vetlugin and Ivan Sokolov from St. Petersburg ...

1980s aircraft helps quantum technology take flight

Oct 20, 2014

What does a 1980s experimental aircraft have to do with state-of-the art quantum technology? Lots, as shown by new research from the Quantum Control Laboratory at the University of Sydney, and published in Nature Physics today. ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

vacuum-mechanics
1 / 5 (5) Jul 21, 2013
"The laws of quantum mechanics which govern the microscopic world are very different from classical physics that rules over large objects such as live beings," explains lead author Lvovsky. "The challenge is to understand where to draw the line and explore whether such a line exists at all. Those are the questions our experiment sheds light on," he states.

The idea behind quantum concept is that the rapid moving of a tiny subatomic particle such as electron could create a co-moving wave, while a daily particle such as a gun's bullet could not. This is the reason why quantum mechanics use wave equation instead of classical physics….
http://www.vacuum...17〈=en
natello
Jul 22, 2013
This comment has been removed by a moderator.
Ash1665
1 / 5 (1) Aug 11, 2013
It is ironic how this article used Schroedinger's experiment to support quantum mechanics, when in fact, he created the situation to attack quantum mechanics. I wish quantum field theory was mentioned in this article. Quantum field theory (QFT) solves many paradoxes in physics. I know this, because a great book, "Fields of Color: The theory that escaped Einstein" written by Rodney Brooks introduced me to QFT. Before I read the book, I knew nothing about QFT, but now I am able to point out what quantum mechanics is missing. I would recommend the book to anybody who is interested in reading about physics in layman terms. You can find the introduction to his book by googling "Einstein's enigmas" in quotes.