Quantum Theory

The worst scientific theory of all time

Dr Mark J Hadley

Dept of Physics

Plan

• Introduction to QT

• Why it is bad

• A bad theory of classical Mechanics– Classical probability

• Why the quantum world is different– Why QT is a bad response

• An alternative to QT

Quantum theory

• Predictions are intrinsically probabilistic.

• A state is represented by a vector, , in a complex Hilbert space.

contains the maximum possible amount of information.

• A rule to get probabilities from .

• A rule to describe the evolution of .

Includes

• Quantum mechanics

• Quantum Field Theory

• String Theory

How bad?

1. Quantum Theory

2. Genesis

3. ..

4. .

5. .

Why is it so bad?

• Fails to explain Nature– What is an elementary particle

• Particle spectrum• Fundamental forces

– What is happening in an experiment

• Prevents progress

(x)

• Gives probability information only.

• It is not the particle.

• It does not exist.

• It requires a new meaning to probability

• Cannot say what a particle is..• where it is…• what it is doing.

A bad theory of classical mechanics

• Throwing a projectile at a target.(r,) describes the probability of a

certain result.(r,,z,t) describes the evolving wave-

packet.

• Nothing else can be said about the projectile

A dice throw

(n) gives the probability of a particular result.

• The throw is governed by classical mechanics.

(n) = 1/6

• Why?

(n)

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

1 2 3 4 5 6

0

0.05

0.1

0.15

0.2

0.25

1 2 3 4 5 6

0

0.05

0.1

0.15

0.2

0.25

1 2 3 4 5 6

0

0.1

0.2

0.3

0.4

0.5

0.6

1 2 3 4 5 6

evens

high

lucky

(n)= 1/6

• Not from Newtonian mechanics

• Structure Phase space of initial conditions

+ Deterministic evolution

= Space of final conditions

• Symmetry

• Nothing else

Structural Implications

1

2

3

4

5

6Phase-space of initial conditions

(n)

Boolean Logic

Deterministic evolution

Classical Probabilities

• Satisfy Boolean Logic

• Are a measure of our ignorance of initial conditions.

• Can always be represented as Volume integrals.

Quantum Theory Probabilities

• Do not satisfy Boolean Logic

• Are represented by projections of a vector

• Are an intrinsic feature of Nature

A completely new meaning to probability

Classical and Quantum worlds are very, very similar.

For a single experiment– Can use classical probabilities

• Boolean Logic• Individual trajectories• No complex wave function

For incompatible experiments– Cannot construct a single phase-space of

initial conditions that gives the observed results.

The quantum World is context dependent

• QT is one response– It hides the difference

• State => Evolution => results

– At a cost• A new meaning to probability• No underlying explanation

The quantum World is context dependent

• Explain it with an existing theory– Sensible

• Explain it with a brilliant new theory– Genius

• Don’t explain it– Pragmatist

• Deny that anything needs explaining– Philosopher

The quantum World is context dependent

• Explain it with an existing theory– lazy

• Explain it with a brilliant new theory– insane

• Don’t explain it– loser

• Deny that anything needs explaining– bad loser

Using an existing theory

• Choice between:1. GR

2. GR

3. GR

GR and QT

• Can GR explain context dependent effects?– Yes

• Will it agree with QT predictions?– Yes it has to

Structure + Symmetry & Continuity = all equations of QT

Using GR

• GR allows a non-trivial causal structure– Measurement apparatus can set additional

boundary conditions

• Any Geometric theory of spacetime can have the same structure

From GR to QT

• Can GR get the equations of QT directly?– No (Not yet)– But remember (n)= 1/6

ProgressThe Logic of Quantum Mechanics Derived From Classical

General Relativity Foundations of Physics Letters Vol 10, No.1, (1997)

43-60.

• Topology change and context dependence International Journal of Theoretical Physics Vol. 38

(1999) 1481

• Charge and the topology of spacetimeClass. Quantum Grav. 16 No 11 (November 1999)

3567-3577

• Spin half in classical general relativity Class. Quantum Grav. 17 No 20 (October 2000)

4187-4194

• The orientability of spacetime Class. Quantum Grav. 19 (August 2002) 4565-4571

The Quantum World

• Explain it with an existing theory– GR (sensible)

• Explain it with a brilliant new theory– insane

• Don’t explain it– loser

• Deny that anything needs explaining– Quantum Theory (bad loser)