The Quantum Story: A History in 40 Moments, Jim Baggott, c. 2011.

The Quantum Story: A History in 40 Moments, Jim Baggott, c. 2011.

Einstein.

Planck.

Bohr. Copenhagen.

de Broglie. (pronounced "de Broy")

Heisenberg.

Transition from "old" quantum theory to a new revolution. Heisenberg made the breakthrough; sent it to Born in Göttingen (Heisenberg was in Helgoland, northern Germany, to recover from severe hay fever), who received it warmly. Born did not recognize the matrix math at first; worked with his student Pascual Jordan to do the math. A copy of Heisenberg's paper found it way to Cambridge; a professor there (Ralph Fowler) not impressed but gave it to his 23-year-old student Paul Dirac. Dirac also did the math but disappointed that Born - Jordan had already done it but perhaps Dirac's method was tidier, more elegant.

Regardless, this math eventually became known as matrix mechanics.  Here the author interchanges many different words, suggesting that the "old" theory was being replaced by matrix mechanics, and the "new quantum mechanics."

I've always differentiated quantum theory as the overarching theory, and quantum mechanics as the tool (generally a mathematical tool) to describe / prove / advance the theory.

So, Einstein - Planck - Bohr - de Broglie - the "old quantum theory."

Born of the old school. Heisenberg was his student.

Heisenberg, in developing matrix mechanics (though he did not call it that), began the "new" quantum revolution.

Pauli

• 1920: Sommerfeld -- introduced the "fourth quantum number" -- 
• Pauli's exclusion principle: December, 1924, paper from Pauli to Bohr
• p. 56: but why, only two electrons per orbit?
• "electron spin" -- p. 58 -- not sure who coined the term; could have been Bohr
• it was Paul Dirac who subsequently suggested that if the electron can be considered to possess two possible "spin" orientations then this, perhaps, explains why each atomic orbit can accommodate only two electrons 

Schrödinger
Swiss Alps, Christmas, 1925

• Pauli and Dirac using the new matrix mechanics to derive key features of the hydrogen emission spectrum
• things seemed set; then Schrödinger showed up; intrigued by de Broglie's wave theories
• he will be thorn in sides of Bohr and Heisenberg
• derivation of the quantum mechanical Schrödinger wave equation starting from classical physics
• sought help from Weyl
• six months, six papers: the new wave mechanics was born, January, to June, 1926
• the battle begins: Schrödinger vs Heisenberg; the former: electron wavefunctions

Part II: Quantum Interpretation

Oxford, August, 1926 - Max Born

• Schrödinger: great visual on how wave-particle looked; wave packets arrived; if a large number of wave packets arrived -- high amplitude -- they would "look like" a particle and, then, of course, when the wave packet hit the target, the wave packet would collapse; the waves would collapse; a point impact
• Max Born, a mathematician. Couldn't get Heisenberg's matrix math to work. Abandoned Heisenberg matrix math and started working with Schrödinger's wave functions.
• Max Born at Göttingen.
• Introduced the element of probability.
• Probability removed a stumbling block in quantum.

Copenhagen, October, 1926

• Heisenberg furious; worried about losing out to Schrödinger's wave function theories.
• Beginning of the Copenhagen - Bohr - Heisenberg feud with Schrödinger-Born (began in Vienna; ended up in Zurich).
• north vs south
• north: Copenhagen -- Heisenberg, Bohr
• south: Zurich, Göttingen  -- Schrödinger, Max Born
• Schrödinger intransigence at Copenhagen

Copenhagen, February, 1927 -- the Uncertainty Principle

• Schrödinger intransigence at Copenhagen
• Bohr and Heisenberg more determined than ever
• led to a fundamental discovery
• Heisenberg: deduces the uncertainty principle
• paper to Pauli; Pauli was supportive

Copenhagen, June, 1927

• Bohr on a two-week skiing holiday; much time to think
• electron's particle-like and wave-like activity continued to perplex the physicists
• much animosity
• Heisenberg almost failed to secure his doctorate
• The Copenhagen interpretation; Bohr prevailed

Lake Como, September, 1927: there is no quantum world

• Bohr had won the argument with Heisenberg
• Complementarity was now the heart of quantum
• But except for Bohr, no one understood what he was talking about
• great discussion of Mach
• great discussion of positivism and pragmatism, page 107
• of the Copenhagen school, Heisenberg was the positivist
• the Copenhagen interpretation essentially states that in quantum theory we have reached the limit of what we can know
• a reworking of familiar classical concepts and a descent into metaphysics
• we now have the nut of the problem: physicists can't get beyond visualizing based on classical concepts; the physicists are using classical instruments to try to solve quantum problems
• Einstein and Schrödinger were both realists; neither were present at Lake Como
• they would show up at the fifth Solvay Congress in Brussesl, where Bohr would repeat his lectur on complementarity

Part III

Quantum Debate

The Debate Commences
Brussels, October, 1927
Fifth Solvay Conference

• first Solvay conference had been held in 2011; sponsored by Planck and Nernst, chaired by Lorentz
• founders of quantum theory: Planck, Einstein, Bohr, de Broglie
• new generation of quantum "mechanics": Born, Heisenberg, Paul, Schrödinger, Dirac
• all in attendance
• Bohr unable to withstand Einstein's objections
• Einstein remain unconvinced

An Absolute Wonder
Cambridge, Christmas, 1927


The Photon Box
Brussels, October, 1930

A Bolt From The Blue
Princeton, May, 1935

The Paradox of Schrödinger's Cat
Oxford, August, 1935

Interlude

The First War of Physics

Christmas, 1938 -- August, 1945

An incredibly short chapter, but one of the best. The meeting between Bohr and Heisenberg. It was clear that Heisenberg supported Hitler's regime. Bohr was not moved. He escaped occupied Copenhagen and eventually made his way to Los Alamos where he was an important player. 

Part IV

Quantum Fields

Shelter Island
Long Island, June, 1947

Pictorial Semi-Vision Thing
New York, January, 1949

A Beautifu Idea
Princeton, February 1954


Some Strangeness in the Proportion
Rochester, August, 1960

Three Quarks for Muster Mark!
New York, March, 1963

The 'God Particle'
Cambridge, Massachusetts, Autumn, 1967

Part V

Quantum Particles

Deep Inelastic Scattering
Standford, August, 1968

Of Charm and Weak Neutral Currents
Harvard, February, 1970


The Magic of Colour
Princeton/Harvard, April, 1973

The November Revolution
Long Island/Stanford, November, 1974

Intermediate Vector Bosons
Geneva, January/June, 1983


The Standard Model
Geneva, September, 2003

Part VI

Quantum Reality

Hidden Variables
Princeton, Spring, 1951

Bertlmann's Socks
Boston, September, 1964


The Aspect Experiments
Paris, September, 1982


The Quantum Eraser
Baltimore, January, 1999

Lab Cats
Stony Brook/Delft, July, 2000

The Persistent Illusion
Vienna, December, 2006

Part VII

Quantum Cosmology

The Wavefunction of the Universe
Princeton, July, 1966

Hawking Radiation
Oxford, February, 1974

The First Superstring Revolution
Aspen, August, 1984


Quanta Of Space and Time
Santa Barbara, February, 1986

Crisis? What Crisis?
Durham, Summer, 1994

Epilogue

A Quantum of Solace

Geneva, March, 2010

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