Does the world we live in exist? Scientists say no – at least not until it’s measured anyway, and this would pertain to small scale. For Australian scientists, recreating experiments confirmed quantum physics’ predictions. The existence of reality is questionable.
If this sounds complex, not to worry. This experiment poses one simple question: Since some elementary particles act as a particle or a wave, then when is this classification decided? This question pushes us to understand how reality is established.
Most people assume that objects such as electrons or photons either wave-like or particle-like just because that’s the way it is. They think that measurements aren’t necessary to come to either conclusion. Quantum theory disagrees and suggests that conclusions can only be made by measurements taken at the end of the object’s journey.
Andrew Truscott of the Australian National University said:
“Reality doesn’t exist unless you look at it, and measurements mean everything.”
The experiment in question is the John Wheeler’s Delayed Choice experiment, first suggested in 1978. This experiment was ahead of its time, and not until 40 years later, utilized to its full potential. Using helium atoms scattered by laser light, scientists set out to measure the journey of objects in our reality.
Roman Khakimov, a Ph.D. student working on the experiment, said:
“Light is more like a wave, so we use atoms, which are more complex. Atoms have mass and interact with electric fields.”
Scientists placed a number of atoms in a suspended state, known as the Bose-Einstein condensate. After capture, all but one of the atoms were ejected. This atom was then placed within a pair of laser beams, to scatter the path of the object, creating a “grating” pattern. The process is similar to how light is scattered when falling upon a grating. After the atom passed through the first grating, a second grating was dropped, intersecting the paths, which added destructive or constructive interference.
This result is an action pointed toward a wave, which can travel both paths. If the second grating is not added, the atom travels only one path, which points toward particle. This suggests that the atom doesn’t know its nature until it passes through a second grating.
“These experiments prove that particle-like or wave-like existence is only possible when measured at the end of the journey. There is no travel from point A to point B. It’s not that simple.”
Using these theories, we are able to develop lasers, LEDS and computer chips. This may sound strange, but it’s just a part of a quantum theory that governs the small world. Until now, these pure experiments weren’t possible. Now, these demonstrations confirm these ideas work.