Quantum theory supports the idea that reality depends on perception. Science has been blurring edges between physical phenomenon and unseen and abstract aspects of the Universe for ages. Reality is a concept that intrigues philosophers, artists and scientist alike and many theories and speculations have been around regarding it. The latest to circulate in news is the experiment conducted by researchers at Australian National University (ANU), which resulted in the development of a new theory: reality does not exist unless we measure it.
The scientists conducted John Archibald Wheeler’s delayed-choice thought experiment which was derived from the double-slit experiment. The double-slit experiment shows the dual behaviour of light, i.e. it acts both as a wave and as a particle. This version of Wheeler’s experiment, however, revealed a new perspective. To conduct the experiment, ANU team trapped multiple helium atoms in a suspended state, called Bose-Einstein condensate. The Bose-Einstein condensate (BEC) is the state of matter in which a dilute bose gas is cooled to near absolute zero. The suspended atoms were then ejected until a single atom remained behind. The atom was then dropped to travel through a pair of laser beams, creating grating pattern which served as crossroads in the same way as solid grating would cause light to scatter.
After this, a second light grating was added randomly to recombine the paths of the atom. This caused constructive and destructive interference, as if resulted by the atom travelling both ways. No interference could be seen when the second random grating was not added - as if the atom had travelled one way only.
“If you choose to believe that the atom really did take a particular path or paths then you have to accept that a future measurement is affecting the atom’s past,” said Professor Truscott.
“The atoms did not travel from A to B. It was only when they were measured at the end of the journey that their wave-like or particle-like behaviour was brought into existence,” said Truscott further.
From what our common sense tells us, whether an object behaves like a particle or a wave is quite independent of our perception. The quantum theories contradict this by asserting that it does not matter if an object acts like a wave or a particle; it’s behaviour depends on how we measure it at a particular point of its journey. Though much remains to be argued philosophically and scientifically, the experiment has given us much to think.
“It proves that measurement is everything. At the quantum level, reality does not exist if you are not looking at it,” Associate Professor Truscott said.The quantum theory deals with the Universe at the smallest level; this new theory added to the magnificence of this area of science and promises us many surprises in the future.