• Boolean Bit
  • Circuit Bit
  • Physical Bit
  • Quantum Bit
  • Classical Bit

There are some important rules about Bits

  • information can be acquired by observation, experiment and measurement
  • subjective
  • the uncertain will up and down
  • information can be lost through coding or itself
  • physical information is localized on space and time

Boolean Bit: Function
Circuit Bit: Combinational logic circuits
Control Bit: Computer Programe
Physical Bit: Dot to store

Quantum Bit

There are two states of a small object, just be expressed by |0 |1.

There are three properties of q-bit:

  • Reversibility: one state can lead to another by means of
    some transition, then the reverse transition is also possible. There are two reasons that can cause the irreversibility of q-bit:

    1. the state of the environment is unknown, then some of the information in the system is lost.
    2. the very act of measuring the state of a system is irreversible.

  • Superposition: Messurement can change the character.

  • Entanglement: Space can be ignore.