Summary (Quick Recall)

Date 04/30/2025

Reviewed On MM/DD/YYYY

Quantum Random Number Generator(QRNG) uses quantum physics in-order to generate a random number. Reason for these notes is because software is unable to generate true random number. It can only generate pseudo random numbers. What this basically means is that we can alway figure out how that randomness occurred.

In QRNG, it uses the quantum properties of the electrons to truly generate a random number.

Key Concepts & Takeaways

  • Xener Diode: Is a diode that allows current to not only flow in the normal forward direction, but also the reverse direction when voltage exceed a certain value.
  • Depletion Zone: Region around the p-n junction of a diode.

Notes

  • Inside of these Xener diodes are two materials p-n. These are materials are filled with atoms. The n-material are positively charge and the p-material is negatively charged.
    • The charge is not strong when it is not be biased by a current.
  • Around the atoms on either material there is Valence electrons which are interacted with the electrons that are following from one material to another. When this happens a Valence electron can be knocked loose or stuck in the depletion zone.
    • When this happens the causes the flow of electrons not to be constant which leads to some randomness. The reason why is the interaction of the electrons are purely random.
    • Another case is quantum tunnel in which electrons pass through the depletion zone in when it shouldn't be able to cross because it doesn't have enough energy.
  • Classical Physics: When a ball attempts to roll up a hill with not enough energy it will stop and roll back.
  • Quantum Physics: When a electron with wave-like properties. Though it may not have enough energy to cross the barrier in my example a hill. There would still be a non-zero probability that it will appear on the other side of the hill.
    • As if it tunneled through the barrier(hill).

Mnemonics / Memory Aids

  • 🎲 True vs Pseudo Randomness
    • 🔁 "Pseudo = Predictable; Quantum = Chaos Unleashed."
    • Pseudo-random numbers are generated by algorithms → can be recreated.
    • Quantum randomness comes from nature’s unpredictability at the electron level.
  • ⚡ Zener Diode Behavior
    • 🔀 "Zener = Zen Flow Both Ways (if over-biased)"
    • Think of Zener as calm but flexible — it lets current flow backward when voltage exceeds a breakdown threshold.
    • Useful for creating instabilities in electron behavior = randomness source.
  • Depletion Zone
    • 🚧 "Depletion = Dead Zone Between Doped Densities"
    • This is the no-man’s land between p-type (positive) and n-type (negative) material.
    • Not many free carriers → critical for tunneling and randomness.
  • ⚛️ Valence Electrons and Tunneling
    • 🌌 "Quantum = Chance, Not Certainty"
    • 🎳 "Ball on a hill = Classical"
    • 🌀 "Wave through a wall = Quantum"
    • Electrons behave like waves in quantum mechanics.
    • Even if they “shouldn’t” have enough energy, they can tunnel through a barrier.
    • Think of tunneling like cheating classical physics using probability.
  • Randomness from Zener Events
    • ⚡ "Zener Glitches = Quantum Twitches"
    • As electrons jump around randomly due to quantum effects, voltage or current output fluctuates — perfect for entropy.
  • 🔄 Electron Interactions = Randomness Source
    • 🔃 "Knock, Stick, or Tunnel — Every Interaction is a Roll of the Dice"
  • Whether an electron:
    • Gets knocked loose
    • Gets stuck
    • Tunnels through
  • The result is inherently unpredictable → perfect for QRNGs.