## Quantum computing versus classical computing

**Quantum Computer vs. Classical Computing**

Classical

- A classical CPU has a series of registers made each of a line of bits.. A single register can have 8 or 32 bits, but most computers today are 64 bit registers.
- An eight bit register is capable of holding 256 different binary numbers or 2 to the eighth power or 256.
- However the register can only hold 1 of those 256 numbers at a time.
- In order to add processing power, you simply add more registers or CPU’s.

Quantum

- Now Quantum computers use Qubits, which are sub atomic particles as the key elements of QC processing.
- And, a quantum computer, due to a quantum physics characteristic called superposition, can hold all 256 numbers at the same time, vs only 1 with Classical.
- So a QC can consider all 256 input combinations at the same time, and thus has exponential growth.
- So 16 qubits would equate to 2 to the 16
^{th}power and simultaneously hold 65,536 different input combinations - With only 24 qubits the processor would be 2 to the 24
^{th}power could simultaneously hold over 16 million different combinations - And with only 300 qubits a QC would have more input combinations than there are atoms in the universe. (2 to the 300
^{th}power). - So while classical computers grow linearly, QC power grows exponentially
- In the end Quantum computers are massive parallel processors with a power unlike anything we have ever known.