Cats, Qubits and Entanglement

Cats, Qubits and Entanglement

Part One of a two-article set of short articles on quantum computing

It’s no surprise that the quantum world is full of surprises and uncertainty. Cats being both dead and alive inside a box, entangled particles supposedly communicating faster than the speed of light, and wave-particle duality are just some of the mysteries that the vast majority of people often encounter, but seldom understand.

Scientists, however, pushed their creativity to the limits and realized the potential that computers designed on the principles of quantum mechanics possess, enabling them to work much, much faster than classical computers.

Quantum computers work on the following principles

  • They take advantage of the fact that particles can exist in multiple states at once. Since computations often require several quantities to be processed, quantum computers are ridiculously fast. (In theory).

  • They replace the classical idea of a bit with a quantum bit, or, Qubit. These are similar to bits, but they replace the notion of bits taking on only 2 states (0 or 1) and instead take a wide variety of values between 0 and 1.

  • The measurement of any quantum state directly impacts the observed values, implying that one simply cannot monitor each step of a calculation without imposing a compounding effect that drastically changes the outcome.

  • And finally, they utilize probabilistic methods to calculate the outcomes. Since qubit states aren’t simple 0s and 1s, and they take multiple states simultaneously, the final outcome depends on which state is most likely for a qubit.

As you might have observed, quantum computers have a major drawback that prevents them from effectively working as fast as they should—error. The larger the number of qubits used, the greater the chance of errors in the outcome, and hence greater the number of error-correcting qubits required to ensure accuracy.

In theory, a 300 qubit quantum computer could simultaneously perform more computations than there are atoms in the universe. That number is far too large for the human mind to fathom. The reality, however (presently) requires billions of additional qubits to ensure that the outcome is accurate.

Thus, quantum computers are an amazing, fascinating piece of technology, whose scope and potential entices scientists to further study and improve upon them. Are they industry ready? Not even close.

Does that mean we should give up? Absolutely not.

Written by Shrenik Kalambur, Head of Research at MIST

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