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Quantum Computing

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This recent announcement from Google is absolutely jaw-dropping. Google says that its 54-qubit Sycamore processor was able to perform a calculation in 200 seconds that would have taken the world’s most powerful supercomputer 10,000 years. Is this real?  Many of you have been asking me what quantum computing is all about? So, I will cover some fundamentals of quantum computing in this blog.

Quantum Computing is an emerging field that applies some basic principles of quantum mechanics to process information at radical speeds. A quantum computer uses quantum bits or qubits. A qubit is made up of electrons or photons. Their spin or polarization represents the state of the quantum respectively.

Evolution of traditional computing

Traditional computing has been struggling to capture more and more information in smaller and smaller forms. Accommodating a greater number of states in the system and speeding the switching between these states greatly enhances the computational time while reducing the consumption of energy. Computing has evolved from vacuum tubes, transistors & Integrated Circuit (IC)s, to microprocessors & modern-day quantum computers.

Applying principles of quantum mechanics to computing
  1. Superposition: It is the property of a quantum to be in multiple states at the same time. A bit in a traditional computer has single state of either 0 or 1. On the other hand qubit has a state that is a probabilistic combination of 0 and 1. It means that a single qubit can store exponentially more information than a traditional bit.
  2. Entanglement: It is extremely strong correlation between quantum particles. Due to such correlation, these particles are linked in perfect unison even if separated by great distance. It helps in ‘connecting’ these particles to ‘work together’. This enables computations of results which were otherwise unreachable.
  3. Any attempt to observe or measure a quantum system will disturb it. This property helps work against any adversary providing a very high level of security.
Unique Applications
  1. It can easily find factors of a very large number which has been a very hard problem to solve till now.
  2. It can help simulate quantum systems.
  3. It can search for the best solution through a space of potential solutions.
  4. Quantum Key Distribution (QKD) of entangled qubits allows for the distribution of completely random keys at a large distance solving the very hard problem of sharing secret keys in cryptography.
  5. The third and last property mentioned above helps in providing very high security against any spoofing, tampering or any kind of security attack.

The announcement from Google in October underlines the paradigm shift from traditional supercomputing to upcoming quantum computing which at times is referred to as Quantum Supremacy.

However, there are some key challenges in this path-breaking technology. It requires qubits that behave the way we want them to. However, any disturbance causes them to “decohere” or fall out of quantum state completely breaking down quantum computing. To address this core problem, quantum error correction has already started emerging as an offshoot. In time, more challenges will surface in this nascent field. But man will keep exploring all possibilities to break the computing barriers existing since the time of Turing.

Interested in knowing more? Keep watching this space as I cover some more aspects of quantum computing in the coming months.

The blog was originally posted on GS Lab’s Website. 

Author: Sameer Mahajan, Principal Architect at GS Lab