Quantum Computers – A Promise for future?

Quantum world is quirky in nature. Once Einstein said “Quantum theory yields much, but it hardly brings us close to the Old secrets. I, in any case, am convinced God does not play dice with the universe” describing the probabilistic nature of quantum physics which is the essence of the subject. Any problem in physics that we can’t seem to explain, we turn towards quantum physics. This shows the beauty of the subject in giving answers to the unanswered questions of nature.

The present-day classical computers use electric pulses based binary inputs (0s and 1s). Every button you press has its own binary coding. In contrast, Quantum computers use Qubits (Quantum bits) which are governed by quantum phenomenon such as entanglement and superposition which enables it to perform much more tasks simultaneously as compared to classical computers. Recently Google showed that its 33 Qubit sycamore processor could perform an arbitrary calculation in 200 seconds which IBM claims that its supercomputer would have done in 2.5 days which is a pretty great difference keeping in view the early stage of the technology.[1] So what are these Qubits?

Qubits are made, for instance, by the spin of electrons which due to superposition can be in many different states all at once but when we try to measure the state, all the Qubits corresponding to wrong answers, collapse and only the right one is observed. The computation is done by algorithms which are choreographed in such a way that has a high probability of landing on the correct answer. That’s what makes quantum mechanics fascinating. What normally is forbidden in our classical world, it happens in the quantum world.

’An invisible thread connects those who are destined to meet, regardless of time, space and circumstances. The thread may stretch or tangle but it will never break.’ Just like these threads, Qubits can also be linked together through entanglement that connects two particles even when the two are at other ends of a galaxy. A measurement on one can instantly affect the other, which was called by Einstein as ”spooky action at a distance”. Consider it like you observe two parties (A and B) that are linked together in such a way that they feel the exact opposite emotion to one another. A is angry, if at the same instant we observe B it would have exact opposite emotion i.e fear. We could say A sent a signal to B and B changed it’s emotional behaviour exactly before we could observe, information travelled faster than light or the observation of the state of one affects the other, they are linked together. In scientific terms, entanglement between two particles can show similar correlation or anti-correlation of measurement outcomes of the quantum states. The collapse of states can occur instantly irrespective of the separation between the two entangled particles.

Quantum computer chips are of the ordinary chip size; they have little coils in which the Qubits (electrons) flow and they interact via Josephson’s junctions and the two Qubits which are very close to one another are entangled. There are other ways to make quantum computer circuits about which you can read from these references [8,9]. We could program how these Qubits would interact. So far so good but why aren’t we using this much promising technology?

Firstly, for these chips to work or show quantum effects they should be cooled to roughly -273°C so as to act as superconductors and act as Qubits. For this purpose, we use coils which apparently make a quantum computer of size of a closet.[3]

Secondly, Qubits show quantum behaviour in very isolated conditions and thus it is extremely fragile and deviates from quantum behaviour due to interaction with the surrounding which is known as quantum decoherence.[2]

Despite all these shortcomings, technological giants like Google and IBM are investing in this technology. We are also seeing independent research institutes in universities like IQC at the University of Waterloo. Currently, we have reached a 60 Qubit quantum computer by Honeywell as compared to IBMQ of 53 Qubits [4]. Rapid progress is going on and for it to use it as an alternative we have to reach at least 160 Qubits. But are these efforts enough? It is believed that if we double the advances every year (i.e. two times Moore’s law) then we could see a quantum computer ready for dominance in the next 10 years.[3]

Given the complexity of quantum computers, their resourcefulness until now is suited for computer simulations of real molecules. The application of quantum physics is not only restricted to quantum computers it has a prosperous future for other fascinating technologies like quantum communication, quantum internet and quantum energy teleportation. If Quantum communication is like mailing a letter, entangled photons are kind of like an envelope: they carry the message and keep it secure. Quantum internet which is a more secure way of transferring data and may be seen by 2030. [11] So far we are able to teleport quantum information but there is a promising field of quantum energy teleportation and it may open a future for teleportation of energy, matter and who knows the physical being itself! [5,6,7]