Quantum Computing

This article highlights about the revolutionary concept in computing field called the Quantum Computing. It examines the possibility of computing at the quantum level, that is at the level of atom and molecules size.

Key Objectives:

· To harness the power of atoms and molecules.

· To perform calculations billion of times faster than today’s silicon based computers.

· Quantum properties of particles can be used to represent data structure.

· Quantum mechanics can be used to perform operations with these data.

Current Technology :
· We use silicon based computers
· Information is stored in form of 0’s and 1’s
· Bit System is represented as Yes or No, True or False, High or Low.
· By the use of Optical lithography techniques, we are able to pack more transistors on a Silicon based semiconductor chip making the processors more faster every year.
· Based on Moore’s Laws (Proposed by Intel’s Co-founder Gordan Moore in 1965).

Moore’s Law :

1. Processing power (no. of transistors and speed) of computer chips was doubling every 18 months or so.

2. With the increase in processing power the size of each transistor gets reduced.

Limitations of Moore’s Law :

If Moore’s Law continues unabated, each transistor would be as small as hydrogen atom by the year 2030, where quantum nature of electrons become significant and will generate errors in computation process.

This is due to the Wave-Particle duality principle as stated by Louis De-Broglie in 1920 : “As object approaches to atomic level, it begins to show dual nature given as : λ = h/mv”

However it is possible to exploit this quantum nature to do high computation by applying quantum mechanics on computers

Definition:

A Quantum computer is any device for computation that makes direct use of distinctively quantum mechanical phenomena, such as superposition and entanglement, to perform operations on data. In a classical (silicon based) computer, the amount of data is measured by bits, but in a quantum computer, the data is measured by qubits.

The basic principle of quantum computation is that the quantum properties of particles can be used to represent and structure data, and that quantum mechanisms can be devised and built to perform operations with these data.

Bit system

Ø Yes or No
Ø True or False
Ø High or Low
Ø 1 or 0
v Includes only Boolean AND, OR and NOT function

Qubit System

Ø Shade of Yes or No
Ø Intermediate states of True or False
Ø In-between states
Ø Combination as 00, 01,10, 11
v Includes Boolean XOR, XNOR, etc.

“300 qubits can store more than 10⁹⁰ numbers simultaneously which is more than no. atoms visible in universe. This shows the power of quantum computers.”

Representation of Qubit in computers :

· Ion traps
· Nuclear magnetic resonance
· Quantum dots

Quantum Phenomenon :

· Quantum parallelism
· Quantum interference
· Quantum entanglement
· Quantum teleportation

Applications in quantum computer

· Molecular stimulation:

Quantum computer can stimulate chemical interactions allowing chemist to learn more about product interaction. Pharmaceutical research will be able to benefit a lot from this development.

· True randomness:

Quantum computers can generate random numbers with true randomness giving more accuracy in program processing

· Representing data structure:

Qubits can be used to represent data structure such as linked list in a more modified way taking less memory and process with high speed using XOR function.

· Encryption technology:

Encryption schemes currently taking million of years to guess can be checked by quantum computers within a year

· Ultra secure, super dense, communication:

Qubits can allow more information to be communicated per bit than same number of classical bits.

· Improve error correction and detection:

Recovering the information from the noisy transmission path will be faster and accurate.

Recent Developments:

· In 2005, researchers at the University of Michigan built a semiconductor chip which functioned as an ion trap. Such devices, produced by standard lithography techniques, may point the way to scalable quantum computing tools.

· On 13 February, 2007 D-Wave Systems Inc. (dwavesys.com) ran an initial demonstration of their Orion quantum computing system, which is built around a 16-qubit superconducting adiabatic quantum computer processor.

· Very recently, many researchers have begun to investigate the possibility of using quantum mechanics for hypercomputation - that is, solving undecidable problems.