#TechTalksWithMelwyn – The Only Supremacy We Want Is Quantum
This week on #TechTalksWithMelwyn we delve into the much talked about Quantum Supremacy and the tech giants all going all out on how to take this forward.
In October 2019, while we were still trying to figure out how to continue watching F.R.I.E.N.D.S once Netflix dropped it, Google made a very important announcement to the world that they achieved Quantum Supremacy. Don’t worry, we ignored it too, until now.
No that is not the new chandelier in Google CEO, Sundar Pichai’s house. Instead, it is the 54-qubit Sycamore processor that was able to perform one particular calculation in 200 seconds, something the world’s most powerful supercomputer would have taken 10,000 years to solve – in short impossible. While Pichai has claimed this leap to be similar to the 12 second flight time of the first flight by the Wright brothers, IBM has been vocal about some glitches with the underlying calculations.
What is Quantum Computing?
In 1900, physicist Max Planck proposed that energy wasn’t emitted continuously but instead in discrete packets (aka quanta) and this was later used by Albert Einstein to explain the photoelectric effect, for which, he won the Nobel prize. Currently, in what we call classic computation, all data exists in transistor chips either as 1s or 0s or a combination thereof. The only way to make processing faster is to reduce the size of the transistor chips and cram more of them into the same space. As you must have guessed, we can only reduce the size to a point before all we end up with are just atoms. And once we reach a size so small, it no longer occurs in the realm of physical laws that we know of and instead is in the realm of quantum mechanics. In 1981, physicist Richard Feynman raised this exact question about whether we can build a computing device that can operate using these principles of quantum mechanics.
Conventional computers work by storing information on a chip as a bit that is either 1 (on) or 0 (off). So a 2-bit computer could have the following states 00,01,10, and 11 at different intervals of time. A quantum computer uses what we call a qubit, and this can be in both states (1 and 0) at the same time. Therefore, in the case of a 2-qubit quantum computer, we can have all the 4 states (00,01,10,11) at the same time. Now if we had to perform a calculation using these 4 states, we could perform it almost instantaneously with a quantum computer as opposed to the four stages with a conventional computer. The only problem here is that we don’t know how to make the quantum computer reveal the answer to us since the qubit is not a real end state but more of a transitionary phase. This concept can be better understood using the analogy of an in-progress coin toss, where the coin is still flipping through the air and can be both heads or tails at any point in time.
The management and generation of Qubits is a complicated task and companies such as IBM, Google, and D-Wave use superconducting materials at a very low temperature (yes, colder than space), while some others use individual atoms trapped in electromagnetic fields in ultra-vacuum. Luckily for us, there are three main concepts to learn to understand quantum computing:
- Superposition: This is the ability for a quantum to be both 1 and 0 at the same time (remember the coin toss). The problem here is that we can only have a finite result once the qubits are measured, at which point they collapse to either 1s or 0s and lose their quantum states.
- Entanglement: We can entangle qubits such that a change in one qubit can instantaneously change the other in a predictable way even if they are separated by long distances. The great part about this is that adding extra qubits can exponentially increase its capabilities. The not so great part is that nobody knows how or why this works.
- Decoherence: This is the end of the qubits behaving like the quanta we want them to behave as either due to planned decay or due to environmental noise (vibrations/temperature etc.). At decoherence, they end up as either 1s or 0s and lose all the computation power they enjoyed as qubits.
Why do we need this?
Quantum computing has several use-cases that we currently can’t provide for with all our supercomputers and storage space. A few examples are :
- Cryptography: The time taken to break down codes or ciphers can be expensive or impractical using current methods. A quantum computer could do this exponentially faster, and this has prompted the NSA (National Security Agency, remember Snowden?) to create a list of quantum-resistant cryptography methods which are currently under review of the National Institute of Standards & Technology.
- Weather Forecasting: Predicting the weather accurately involves many variables and sometimes takes computers longer to simulate than for the actual weather to evolve. Quantum computing can help incorporate all these variables to provide greater weather accuracy for food production, transportation, etc.
- Molecular Sciences: As per a Boston Consulting Group (BCG) paper in 2019, modeling a penicillin molecule would require 1086 bits, which is impossible using a classical computer. On the other hand, a quantum computer could do this in a jiffy and could lead to the discovery of new drugs for cancer, Alzheimer’s, and other severe medical conditions. This capability to analyze molecules is also being tested by Volkswagen and Daimler to enhance battery life for electric vehicles.
According to the MIT technology review, Quantum Supremacy is the point at which a quantum computer can complete a mathematical calculation that is demonstrably beyond the reach of even the most powerful supercomputer. Whether or not Google has achieved it, we are yet to see; but in the interim, we will continue to wish for cures to terminal diseases, better battery technology for electric cars, and better route optimization to save us all from traffic!
