Physics is a subject you either love or hate, as it involves an understanding of the mechanics that makes the world the way it is and allows us to understand the forces that act upon each particle in the universe, and then there is quantum physics. While motion physics is fun to understand and experiment with, quantum mechanics are truly complicated and most of the time leaves one scratching their head as it deals with particles on a microscopic level and one topic of it is Quantum Entanglement.
What is Quantum Entanglement?
Quantum Entanglement in really simple words is the principle of dependency of two events or objects that cannot exist without the other. For example, a person asks you to guess in what hand they are holding the eraser and a sharpener, once you know that eraser is in left hand you are certain that the right hand contains the sharpener, therefore these two are entangled and if one is affected in any shape or form it will have an effect on the other, and before knowing the outcome chances will remain 50%. Unfortunately, as is with quantum physics it is not that simple.
Perhaps one of the most famous experiments conducted in physics, the double-slit experiment revealed that particles have both wave and particle nature, in the past, it was considered either something is a particle or a wave. In the experiment, an electron beam was passed through a sheet with two slits in it and an optical screen was placed behind it. As electrons were considered particles before this experiment, they should’ve simply created a pattern on the screen that would obey the particle nature, however, the pattern that appeared on the screen was similar to wave nature, as if the light was projected through the slits. According to the scientists, this happened due to something known as superposition, which was proposed by Niels Bohr during a conference that was held in Belgium, he stated that a particle exists in multiple states when not observed but as soon as it is observed, it gets fixed in that particular state. This later came to be known as the Copenhagen Interpretation which led to a series of debates between Bohr and Albert Einstein and is regarded as one of the most significant series of debates. Another famous example of this principle was conducted by Erwin Schrödinger and has become synonymous with Bohr’s explanation. Although Schrödinger agreed with Einstein and wanted to conduct this experiment to show the flaws of Bohr’s explanation, it ended up becoming a staple of his theory. This has led scientists to believe that electrons may exist in a different way around the nucleus when not observed.
Now considering the superposition, we can establish that electrons have both negative and positive angular spin. Therefore, when these electrons are not observed they exist in both spin states, and when observed one electron must have a spin up while the other must have a spin down to zero out the system. So in theory, if we were to hypothetically separate these electrons by say a million lightyears, if we observed the spin of one electron, we’d instantly know the spin of another electron. Hence, this information traveled millions of lightyears in an instance and as proposed by Albert Einstein, nothing can travel faster than light, undoubtedly, he disagreed with this idea and called it spooky action at a distance. So, what could be the possible applications of such a strange idea?
Applications of Quantum Entanglement
So now that we know what Quantum Entanglement is, how can we implement such a bizarre idea into the real world? You might be surprised to know that some fields are already utilizing it.
- Cryptography and Codes: In today’s world most of our transactions are done online. Online banking was thought to be one of the most secure ways one can send and receive funds, however, a big online theft occurred on the portal of Paypal, and everyone was shaken. The way present technology works are that, a key is generated by the sender which is shared with the recipient, and by using the provided key funds can be shared. Sounds great on paper as long as we don’t consider third-party attacks, if the information of the transaction is leaked or stolen it becomes fairly easy for hackers to rob. While the new encrypted crypto does provide some benefits over it, it still isn’t perfect. Here is where Quantum Entanglement comes into play, and this is known as QKD or Quantum Key Distribution. In this, information is sent in the form of a set of randomly polarized photons which are arranged in only one plane; up, down, left, or right, then the recipient must use a polarizing filter and algorithms to decrypt the information. What makes it secure is that the exact quantum key is required to utilize the information and according to the rule, if one is to breach this information it will result in altering the information as once observed it will change the state and ultimately altering the original communicators. In Switzerland, quantum voting is already being used and a bank in Australia utilizes this system.
- Enhanced Microscopes: Though microscopes are already quite a complex tool, the more advanced product has been created thanks to quantum entanglement and it is the world’s first entangled-enhanced microscope. It uses a technique known as differential interference contrast microscopy. This works in quite a different way from the traditional microscope, in this, two beams of photons are projected onto a substance and the pattern of interference created by the reflected beams is measured and the changes in the pattern depend upon whether the beam of photons hit a flat or uneven surface. Thanks to the entangled photons the information gathered can be measured by simply knowing the state of one photon, it tells us the information about its pairing photon, and with this scientists managed to see the engraving of a ‘Q’ with extreme sharpness. What makes it astonishing is that the Q was raised just by 17 nanometers from the background. According to the experts, astronomy tools can benefit from this technology as well in the future.
- Precise Clocks: While we may think that modern clocks are already pretty accurate, it is still subject to error which could result in many complications. In the past, pendulums were designed and used to keep time, as one swing of a pendulum denoted 1 second, it was all well and good but they were prone to temperature changes, gravity, and manufacturing errors. Following that, Quartz clocks were invented which proved to be very precise and is still the standard material used in clocks and each quartz oscillator used in modern clocks is designed to vibrate at 32,768 m/s. Though very precise, they are still subject to errors and that’s the reason why atomic clocks are used in GPS and CERN where the accuracy of milliseconds is required when smashing atoms in a system. In atomic clocks, the cesium-133 atom is used which oscillates precisely at 9,192,631,770 times per second, and atoms are kept in a vacuum. While previously created clocks were vulnerable to local differences, these are unaffected by such factors and only track the passage of time without any change.
While scientists are working on other applications of Quantum Entanglement, those are in the future. One company claims to be selling the first commercial quantum computer but is met with a lot of skepticism and scientists are still unclear about its quantum properties. Another scenario, believe it or not, is in the realm of biology where they are studying a particular bird as they claim it uses quantum entanglement to migrate but it is still unclear and not fully understood. Ultimately, the present applications of this are rare but they might change in the future.