The Study of Quantum Communication

1
The Study of Quantum Communication??????????
2
Introduction

• Atom and elementary particles
• atom is the smallest particle of an element that
  still has the characteristics of that element.
• atoms are made from even smaller parts called
  elementary particles (Protons, neutrons, and
  electrons)

3
Introduction

• What is a photon?
• A photon is a force carrier particle.
• Elementary particles (electrons, protons,
  neutrons, and such) can only interact using force
  carriers.
• Photons are responsible for electromagnetic
  interactions.

4
What is qbit?

• Denote
  are 2 basic states of a photon or a elementary
  particle.
• Define a qbit is a 2-dimensional complex valued
  vector in a 2-dimensional Hilbert space.
• Qbit can be thought as electron or photon in
  physic implementation with 2 computational basic
  vector 0? and 1?

5
Entanglement

• The decay of photon
• When a photon passes through Certain crystal
  structures
• firstly, it will be absorbed by an electron
• Eventually, and spontaneously, the electron will
  return to its ground state by emitting the photon
  
• When the original photon decays into two photons,
  the resulting photon pair is considered
  entangled.
• Normally the photons exit the crystal such that
  one has spin down 1? , the other has spin up 0?
  .

6
Entanglement
7
Quantum Teleportation

• Is the way to delivery 1 single particle

8
Multi-user DS-CDMA Detector

• We have
• K the number of users.
• R the number of symbols in 1 burst.
• B b1, b2,, bK Bik bki
  k1,..,K i0,..,R
• sk(t) the analog version of chip sequence
• The received signals

9
Introduction

• So, all the possible values of can
  create the matrix Y Y y1, y2,, yK
  Yik yki

10
Quantum based key distribution
11
Quantum based key distribution
12
Long Distance Non Delay Communication