It is a term proposed in 2012 by John Preskill, professor of theoretical physics at the California Institute of Technology.
It describes the point where quantum computers can do things that classical computers cannot.
In Google’s case, researchers at the University of California, Santa Barbara have claimed to have developed a processor that took 200 seconds to do a calculation that would have taken a classical computer 10,000 years.
What are qubits?
A qubit is the physical carrier of quantum information and can take values of zero, one, or both at once.
Classical computes encode information in bits whereas quantum computers use qubits.
Each qubit can represent both a 1 and a 0 at the same time.
Using qubit, Quantum Computers can hold more information than classical computers and solve problems faster and more efficiently.
In designing a standard computer, engineers spend a lot of time trying to make sure the status of each bit is independent from that of all the other bits.
But in a quantum computer, each qubit influences the other qubits around it, working together to arrive at a solution.
Superposition and entanglement are what give quantum computers the ability to process so much more information so much faster.
Difference between a standard computer and a quantum computer:
- A classical computer performs calculations using bits that is 0 representing off and 1 representing on.
- It uses transistors to process information in the form of sequences of zeros and ones called computer binary language. More transistors more processing ability.
- A quantum computer uses the laws of quantum mechanics.
- Just like a classical computer that uses zeros and ones. These states can be achieved in particles due to their internal angular momentum called spin.
- The two states 0 and 1 can be represented in the spin of the particle.
- For example: clockwise spin represents 1 and counter clockwise represents 0. The advantage of using a quantum computer is that the particle can be in multiple states simultaneously. This phenomenon is called
- Due to this phenomenon a quantum computer can achieve both 0 and 1 states at the same time. Thus, in a classical computer information is expressed through single number either 0 or 1.
- A quantum computer uses quits which is described as a 0 and 1 at the same time giving us more processing power.
- For Instance: In a 2 bit classic computer to analyse 00 01 10 11 , it has to grow through each step to get to a result . In a 2-qubit quantum computer can analyse all the possibilities at the same time. Hence reducing time.