Time: it's no doubt a confusing topic, and it gets even more confusing the more we try to unearth its secrets.
Physicists have been examining the workings of time for decades, and the results published about it are mind-altering to contemplate, to say the least, and show that time might not exist as we think it does.
A new paper titled "Time Crystals from Minimum Time Uncertainty" that was recently revised and re-published in The European Physical Journal marks just one example of the astonishing research being conducted on this subject.
In it, the researchers have proposed that the shortest physically meaningful length of time might really be multiple orders of magnitude longer than Planck time.
Planck time refers to the time required for light to travel, in a vacuum, which would be a distance of 1 Planck length. The unit is named after Max Planck, who was the first to propose the theory.
Nur Faisal from the University of Waterloo, one of the researchers involved in the study, told phys.org that it might be possible for the minimum time scale in the universe to actually be much larger than Planck time.
He also said that this can be,
No experiment has ever come close to examining Planck time directly because it is so short. Nevertheless, as phys.org points out, there is a good amount of theoretical support for the existence of Planck time.
So, how do they figure that time might be much larger than Planck time?
They measured the rate of spontaneous emission of a hydrogen atom:
The researchers also mention that their findings could change the basic equations of quantum mechanics, and would modify the very definition of time that's understood today.
The Illusion of Reality
According to the rules of quantum mechanics, our observations, and as some scientists like to call them, 'factors associated with consciousness,' influence the universe at the most fundamental levels.
When physicists look at reality at the smallest scales, it becomes clear that an atom's behavior is dependant on the physicist's observations.
As per this experiment, researchers noted that our perception of time as something that is continuously flowing is just an illusion.
Faizal is referring to Plato's idea that true reality exists independent of our senses.
Perhaps the true makeup of what we perceive to be reality is beyond our ability to perceive?
The Delayed Choice/Quantum Eraser Experiment
The delayed choice experiment illustrates how what happens in the present can change what happens(ed) in the past.
It also shows,
To understand the delayed choice experiment, you have to understand the quantum double slit experiment, which is used to show how factors associated with consciousness create different behaviors in an atom, as mentioned earlier.
In this experiment, tiny bits of matter (photons, electrons, or any atomic-sized object) are shot towards a screen that has two slits in it.
On the other side of the screen, a high tech video camera records where each photon lands. When scientists close one slit, the camera will show us an expected pattern, as seen in the video below.
But when both slits are opened, an "interference pattern" emerges - they begin to act like waves.
This doesn't mean that atomic objects are observed as a wave (even though it recently has been observed as a wave), but rather that each photon individually goes through both slits at the same time and interferes with itself, but it also goes through one slit, and it goes through the other.
Furthermore, it goes through neither of them.
The single piece of matter becomes a "wave" of potentials, expressing itself in the form of multiple possibilities, and this is why we get the interference pattern.
Then, when an "observer" decides to measure and look at which slit the piece of matter goes through, the "wave" of potential paths collapses into one single path.
The particle goes from becoming, again, a "wave" of potentials into one particle taking a single route. It's as if the particle knows it's being watched.
The observer has some sort of effect on the behavior of the particle.
Multiple experiments have found that factors associated with consciousness "significantly" correlated in predicted ways with perturbations in the double slit interference pattern. (source)
You can view a visual demonstration/explanation of the double slit experiment here.
This quantum uncertainty is defined as the ability,
According to physicist Andrew Truscott, lead researcher from a study (Wheeler's Delayed-Choice Gedanken Experiment with a Single Atom) published by the Australian National University, the experiment suggests that,
It suggests that we are living in a holographic-type of universe. (source)
So, how is all of this information relevant to the concept of time?
Just as the double slit experiment illustrates how factors associated with consciousness collapse the quantum wave function (a piece of matter existing in multiple potential states) into a single piece of matter with defined physical properties (no longer a wave, all those potential states collapsed into one), the delayed choice experiment illustrates how what happens in the present can change what happens(ed) in the past.
It also shows how time can go backwards, how cause and effect can be reversed, and how the future caused the past.
Like the quantum double slit experiment, the delayed choice/quantum eraser has been demonstrated and repeated time and time again.
For example, Physicists at The Australian National University (ANU) have conducted John Wheeler's delayed-choice thought experiment; their findings were recently published in the journal Nature Physics. (Wheeler's Delayed-Choice Gedanken Experiment with a Single Atom)
In 2007 (Science 315, 966, 2007), scientists in France shot photons into an apparatus and showed that their actions could retroactively change something which had already happened.
Asher Peres, a pioneer in quantum information theory, elaborates:
This idea was first brought to the forefront by John Wheeler in 1978, which is why I am going to end this article with his explanation of the delayed choice experiment.
He believed that this experiment was best explained on a cosmic scale.
Cosmic Scale Explanation
He asks us to imagine a star emitting a photon billions of years ago, heading in the direction of planet Earth.
In between, there is a galaxy. As a result of what's known as "gravitational lensing," the light will have to bend around the galaxy in order to reach Earth, so it has to take one of two paths: go left or go right.
Billions of years later, if one decides to set up an apparatus to "catch" the photon, the resulting pattern would be (as explained above in the double slit experiment) an interference pattern.
This demonstrates that the photon took one way, and it took the other way.
One could also choose to "peek" at the incoming photon, setting up a telescope on each side of the galaxy to determine which side the photon took to reach Earth. The very act of measuring or "watching" which way the photon comes in means it can only come in from one side.
The pattern will no longer be an interference pattern representing multiple possibilities, but a single clump pattern showing "one" way.
What does this mean? It means how we choose to measure "now" affects what direction the photon took billions of years ago. Our choice in the present moment affected what had already happened in the past…
This makes absolutely no sense, which is a common problem when it comes to quantum physics. Regardless of our ability make sense of it, however, it is very real.
This experiment also suggests that quantum entanglement (which has also been verified; read more about that here) exists regardless of time - meaning two bits of matter can actually be entangled, again, in time.
Time, both as we measure it and understand it, doesn't really exist...