Quantum Computing: Quantum computing is the use of quantum-mechanical phenomena such as superposition and entanglement to perform computation. Computers that perform quantum computations are known as quantum computers.
The basics of Quantum Computing have been covered here.
The world in which we live is based and run on laws of physics. The gears of physics provide the momentum for the world to function smoothly. But, the gears of physics actually work just as smoothly in reverse.
Maybe Time Travel is possible after all?
Inspite of being a mysterious phenomenon in the quantum mechanical context, Einstein’s theory of relativity considers Time to be just a fourth dimension in our reality. If Einstein’s theory is to be followed, then motion through this dimension should be smooth. Then why is it that time-travel is still a thing only in science fiction?
An experiment from 2019 shows the boundaries that differentiate the past and the present, on a quantum scale. Researchers from the US and Russia teamed up to find a way to alter on the most fundamental laws of physics.
The researchers wanted to bend the second law of thermodynamics. The second law states that the total entropy of an isolated system can never decrease over time, and is constant if and only if all processes are reversible. This small statement is the guiding principle for all the physical processes in the universe. Even when subjected to quantum processes, the second law does not lose its ground.
If you observe carefully, this is the only law of physics that mentions the word time. Other laws of physics are time-dependent, meaning, they work well in the forward time direction as well as in the backward one.
“That law is closely related to the notion of the arrow of time that posits the one-way direction of time from the past to the future,” said quantum physicist Gordey Lesovik from the Moscow Institute of Physics and Technology.
To put it simply: you could zoom in on a game of pool, and a single collision between any two balls won’t look weird if you happened to see it in reverse. On the other hand, if you watched balls roll out of pockets and reform the starting pyramid, it would be a sobering experience. That is the second law.
In the quantum realm, things get a bit different. As we focus in on the tiny gears of reality - in this case, solitary electrons - loopholes appear. Electrons, if we consider, are defined by the space they occupy. We can only give a range of locations where a given particle is likely to be, rather than its definite location. The details of this characteristic of electrons can be properly summed up using the Schrodinger’s Equation. This equation represents the possibilities of an electron’s characteristics as a wave.
If we imagine the same game of pool, as previously discussed, according to the Schrodinger’s equation the balls are somewhere on the pool table moving at a certain speed. But, in quantum terms, the ball is everywhere at a bunch of speeds.
There are certain conditions under which the equation describes a particle localizing into a small region of space, just like a ball coming back into your palm after being thrown.
This thing was simulated in Quantum Computers, and simulations were run, which showed that this could happen after all. The algorithms used by the researchers could assist in potentially improving the performance of quantum computers; other than that, this experiment could provide us with great insights into what could be possible if we can harness the power of quantum physics.