All About Quantum Computing

All About Quantum Computing

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Quantum computing is the area of study focused on developing computer technology based on the principles of quantum theory, which explains the nature and behavior of energy and matter on the quantum (atomic and subatomic) level. Development of a quantum computer, if practical, would mark a leap forward in computing capability far greater than that from the abacus to a modern day supercomputer, with performance gains in the billion-fold realm and beyond. The quantum computer, following the laws of quantum physics, would gain enormous processing power through the ability to be in multiple states, and to perform tasks using all possible permutations simultaneously.

Quantum computing is the study of a non-classical model of computation. Whereas a classical computer encodes data into fundamental units called bits, where each bit represents either a one or a zero, a quantum computer encodes data into bits that can represent a one, a zero, or some combination. The combination is known as a quantum superposition, and bits with these quantum properties are known as qubits. This is in contrast to classical computers which perform computations that never deviate from clearly defined values.

Another defining aspect of a quantum computer is the ability to link qubits together with quantum entanglement. Taken together, these and other properties of a quantum computer may allow them to perform operations on qubits which include computational speed and possibilities not available to classical computers.

Timeline Of Quantum Computing:-

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Quantum computing began in the early 1980s, when physicist Paul Benioff proposed a quantum mechanical model of the Turing machine.

Quantum physics has defied logic since the atom was first studied in the early 20th century. It turns out atoms do not follow the traditional rules of physics. Quantum particles can move forward or backward in time, exist in two places at once and even “teleport.” It’s these strange behaviours that quantum computers aim to use to their advantage.

Classical computers manipulate ones and zeroes to crunch through operations, but quantum computers use quantum bits or qubits. Just like classical computers, quantum computers use ones and zeros, but qubits have a third state called “superposition” that allows them to represent a one or a zero at the same time. Instead of analysing a one or a zero sequentially, superposition allows two qubits in superposition to represent four scenarios at the same time. Therefore, the time it takes to crunch a data set is significantly reduced.

Every day we create volumes of data. In order to adequately process it all to extract meaning from it, we require much more computing power. That’s where quantum computers step in to save the day.

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How a regular computer stores information?

Now, a regular computer stores information in a series of 0’s and 1’s.
Different kinds of information, such as numbers, text, and images can be represented this way.
Each unit in this series of 0’s and 1’s is called a bit. So, a bit can be set to either 0 or 1.

Now, what about quantum computers?

A quantum computer does not use bits to store information. Instead, it uses something called qubits.
Each qubit can not only be set to 1 or 0, but it can also be set to 1 and 0.

Quantum Computing Vs Classical Computing:-

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The key features of an ordinary computer—bits, registers, logic gates, algorithms, and so on—have analogous features in a quantum computer. Instead of bits, a quantum computer has quantum bits or qubits, which work in a particularly intriguing way. Where a bit can store either a zero or a 1, a qubit can store a zero, a one, both zero and one, or an infinite number of values in between—and be in multiple states (store multiple values) at the same time! If that sounds confusing, think back to light being a particle and a wave at the same time, Schrödinger's cat being alive and dead, or a car being a bicycle and a bus. A gentler way to think of the numbers qubits store is through the physics concept of superposition (where two waves add to make a third one that contains both of the originals). If you blow on something like a flute, the pipe fills up with a standing wave: a wave made up of a fundamental frequency (the basic note you're playing) and lots of overtones or harmonics (higher-frequency multiples of the fundamental). The wave inside the pipe contains all these waves simultaneously: they're added together to make a combined wave that includes them all. Qubits use superposition to represent multiple states (multiple numeric values) simultaneously in a similar way.
Just as a quantum computer can store multiple numbers at once, so it can process them simultaneously. Instead of working in serial (doing a series of things one at a time in a sequence), it can work in parallel (doing multiple things at the same time). Only when you try to find out what state it's actually in at any given moment (by measuring it, in other words) does it "collapse" into one of its possible states—and that gives you the answer to your problem. Estimates suggest a quantum computer's ability to work in parallel would make it millions of times faster than any conventional computer... if only we could build it!

The future

Quantum processors based on superconducting qubits can now perform computations in a Hilbert space of dimension 253 ≈ 9 × 1015, beyond the reach of the fastest classical supercomputers available today. To our knowledge, this experiment marks the first computation that can be performed only on a quantum processor. Quantum processors have thus reached the regime of quantum supremacy. We expect that their computational power will continue to grow at a double-exponential rate: the classical cost of simulating a quantum circuit increases exponentially with computational volume, and hardware improvements will probably follow a quantum-processor equivalent of Moore’s law 52,53, doubling this computational volume every few years. To sustain the double-exponential growth rate and to eventually offer the computational volume needed to run well known quantum algorithms, such as the Shor or Grover algorithms 25,54, the engineering of quantum error correction will need to become a focus of attention.

The extended Church–Turing thesis formulated by Bernstein and Vazirani55 asserts that any ‘reasonable’ model of computation can be efficiently simulated by a Turing machine. Our experiment suggests that a model of computation may now be available that violates this assertion. We have performed random quantum circuit sampling in polynomial time using a physically realizable quantum processor (with sufficiently low error rates), yet no efficient method is known to exist for classical computing machinery. As a result of these developments, quantum computing is transitioning from a research topic to a technology that unlocks new computational capabilities. We are only one creative algorithm away from valuable near-term applications.

Quantum Computing-Fully Explained!

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TOP QUANTUM COMPUTING COMPANIES

• Strangeworks
• Zapata Computing
• Coldquanta
• QC Ware
• IBM
• D-Wave Systems

References:-

• https://www.nature.com/articles/s41586-019-1666-5 
• https://builtin.com/hardware/quantum-computing-companies
• https://whatis.techtarget.com/definition/quantum-computing
• https://plus.maths.org/content/how-does-quantum-commuting-work
• https://www.youtube.com/watch?v=PzL-oXxNGVM