• Digression: “Learn to code”. Why?
  • Because the computer code describes a conceptual framework for maintaining and altering “state” (information)
  • And that framework can be generally applied to understand and describe our reality
    • A similar thing can be said about mathematics
  • Computer coding and mathematics are key conceptual tools to understand the world
• Q. What are you made of? A. “Matter” What is “matter”?
• High school description: “made of atoms”
• Basic science description: something with “mass” (inertia when acted on by a force: m = F/a, m = p/v)
• (Special) relativity: E = m* c ^ 2: equivalence of matter and energy (“matter as “frozen” energy, aka a state of energy
• Quantum mechanics: a wave with quantum properties (aka quantum numbers)
  • Digression: “particles” are really waves (wavelets)
  • What are those?
  • States → a la computation: informational states
    • A “setting” (S1 = 3. Setting S1 → 2 is a state transition
    • QM examples: spin values, energy levels, momenta, position
    • Those are all discrete, aka “quantized” values
  • Collection of atoms absorbing and emitting photons is a computational system
• The world is informational
  • Shift from mechanical worldview to informational worldview
  • Information is fundamental
  • Writing down the description of the world, in a sense, is the world
  • Think of the universe as a giant computing engine, combining both processing and data
  • The current state of the universe is the universe is its “state”
  • Over time it will (computationally) evolve into a different state
• Mathematics:
  • If Physics is the “operating system” of the world, Mathematics is its architecture (the underlying structure through which operations are possible)
  • Operation of computer code can be described as manipulation of mathematical equations by operators
    • Simple operator: multiplication (multiply both sides of an equation)
    • More complicated operators do more complex transformations
  • Quantum mechanics:
    • Transitions of wavefunctions’ quantum states as quantum operators are applied
      • Ex. measure an energy level, propagate a light beam through a filter, apply a magnetic field to an atom
  • The commonality of description suggests that our world is fundamentally computational and computational concepts are key to understanding it
• Physics aside: standard model
  • A more complex and nuanced description than simple quantum mechanics but essentially still has everything built from quantum waves (“particles”) mediated by field operators
• World-computer
  • We are evolving towards the idea of the universe as a computer (“world-computer”)
  • The world is fundamentally digital
  • The universe (“world-computer”) stores information in defined physical regions (Plank voxels)
    • Timescale: Plank time
    • Length (volume) scale: Plank length (volume)
• Why is the speed of light the fundamental limit of information propagation
  • It’s not really the speed of light (electromagnetic radiation) per se, that’s actually backwards
  • Reality has a fundamental limit at which information can transmit from one Plank voxel to another
    • This is the “clock speed” of the world-computer
    • In a vacuum, light travels at that speed
      • At a detailed level, the propagation of the light wavefront from the voxels that define it to the next set of voxels (by flipping quantum states) happens at that speed
      • Analogy: jpeg photo of a curve
• Relativity still applies
  • There is no privileged frame of reference
    • Ex. An apparent electric field in one frame may appear as a magnetic field in another
  • There is no “neutral observer”; to make a measurement we must have an observer in space and what that observer can measure is actually the relativistically transformed quantum transition (ex. Shifted wavelength)
• Randomness
  • Underlying “sea of randomness” manifests through quantum transitions
    • Examples:
      • Photon emission
      • Radioactive decay
      • Tunneling through a barrier
  • Complex, loosely bound systems as a better “antenna for randomness”
• Entanglement
  • Underlying (geometric) connection where measuring (determining) state of one object causes its entangled counterpart to instantly assume the same state
• Chemistry
  • Atoms of different types have different wavefunctions
  • As they come together, they form a system (molecule) which has its own composite wavefunction
  • Sharing electrons across (parts of) the molecule creates chemical bonds
• Summary: Properties of reality (“spacetime”)
  • It is separated into discrete spacial “voxels” at the Plank volume
  • Seen at a fine enough level (Plank voxel) all other structure, including waves, disappears and we have only the quantum state of that voxel
  • “Time” is measured in clock ticks (at the Plank scale)