Quantum Computing

•In Oct 2019 Google announced that it was building a quantum computer with 54 qubits in collaboration with NASA.

•This computer can solve a problem in 200 sec which would have taken 10,000 years for the World’s Fastest Supercomputer.

What is quantum computing

•Area of study focused on development of computers based on quantum theory.

•Quantum theory explains behaviour at quantum(atomic or subatomic) level.

•It uses Qubits whereas a classical computer uses Bits.

•These computers are much powerful than a classical computer.

History

•In 1981, Paul Benioff proposed with essential elements of quantum computing.

•He also proposed a quantum model of the Turing machine.

Quantum Theory

•It began in the 1900s where Max Planck introduced the idea that energy and matter exist in individual units called quanta.(or quantized)

•In 1905, Albert Einstein proposed that radiation was also quantized in the same manner.

•In 1924, Louis de Broglie said that there is no difference and at subatomic level matter or energy can exist as both particles or waves.

In 1927, Werner Heisenberg said that it was impossible to make simultaneous measurement of 2 complementary properties.

Schrodinger’s cat: A cat is in a box with a bottle of cyanide and the box is closed. The cat is in superposition state i.e. it is both dead and alive.

The principle that one particle can exist in numerous states opens up profound implications for computing.

Qubits

•Qubits make use of 2 key principles of quantum physics: Superposition and entanglement.

Superposition

•It can give 1 or 0 or both.

•In this a particle exists in multiple states at the same time and its impossible to determine both the parameters simultaneously.

•It helps us to store and manipulate vast amounts of information in relatively small amounts of particles.

Entanglement

•It is the entanglement of 2 superposition, a process called correlation.

•The value of 1 qubit depends on that of the other.

•Qubits can be separated by huge distances and still be entangled provided that they are isloated.

Comparison of Classical and Quantum Computer

Classical Computer

•Data can be processed in bits(1 or 0).

•It has 2n system states where n is the number of bits.

Quantum Computer

•Data can be processed in qubits(1 or 0 or both).

•It has 2^n system states where n is the number of qubtis.(no. of bits it can examine 1 at a time)