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Few people actually understand all the extremely complex goings on behind quantum mechanics, and of those who do, most are quantum physicists. That’s not to say that all quantum physicists actually understand quantum mechanics, but just that most people who understand it tend to have a job in the field. After rehashing an old theory, a team of quantum physicists show quantum surrealism demonstrated via De Broglie-Bohm theory.
The uncertainty principle
For those of us not in the know, the uncertainty principle in quantum mechanics refers to the fact that it’s impossible to know both a particle’s momentum and position with certainty. This is because if any interaction is attempted with a quantum system, it will end up effectively disturbed.
According to this quantum mechanics interpretation, there actually isn’t any real trajectory between the source of light and the screen if we were to launch a photon from one to the other. It also claims that the best we can hope for is to calculate something referred to as a wave function, which shows the chances of the photon being in any one place at any one time, but it won’t give us a location until we make an actual measurement.
A different interpretation, called the De Broglie-Bohm theory, states that photons do actually have real trajectories guided by something called a pilot wave, which accompanies the aforementioned particle. Despite the wave still being up to probability, according to this theory the particle has a real trajectory.
Quantum surrealism
By launching many photons from a light source at a screen, a team of researchers led by University of Toronto’s Aephraim Steinberg in 2011 measured them very, very slightly, so little actually that their trajectories were barely affected. With the help of the multiple measurements, however, a plausible trajectory was estimated.
Despite the trajectory being similar to the traditional approach, looking pretty much like balls flying through the air, this approach was criticized for ignoring the fact that measuring the particles can lead to it getting entangled with another, disturbing both of their trajectories. This incorrect prediction of the particles’ trajectories is referred to as a surreal trajectory.
By launching photons through a slit and onto a screen and then tracking them, Steinberg and his team recently observed the nonlocal influence another photon had on the launched photon after getting entangled with it.
This counters the critique of the De Broglie-Bohm theory which states that it doesn’t realistically explain the behavior of the photons. However, according to Steinberg, the philosophical and metaphysical issues aren’t really relevant, as the procedure can offer us a much needed way of actually visualizing the trajectories of photons.
Image source: Wikimedia
