HSCI - The Fields of Physics

Metaphor of building a cathedral for the development of scientific theories

New theories of physics are built on older theories back in the 1900’s, like the evodevo arches and scaffolds metaphor. This is based on the Sagadra Familia, where the theory of Quantum Gravity is the unfinished spire at the top, built on Quantum Mechanics and General Relativity. The base is composed of classical mechanics, optics, electrodynamics, and special relativity. Supporting quantum mechanics are classical mechanics, thermodynamics, and statistical mechanics.

• The cathedral is a better metaphor for this scenario as the scaffolds supporting the arches cannot be dropped, and each section is built in a unique style. It is much more complex and interwoven.

Coulomb (General Relativity)

Helped develop the field of electromagnetism by formulating a law for the attraction between two charged spheres, inspired by Newton’s model.

Galvani (General Relativity)

Helped develop the field of electromagnetism and experimented with frog legs, which twitched, he considered this magnetism.

Volta (General Relativity)

Helped develop the field of electromagnetism by taking Galvani’s findings and adding that acidic material between two metals creates a current. He then constructed the first battery, called the voltaic pile. This development was integral for safe experiments, giving scientists a better handle on electricity.

Orstedt (General Relativity)

Helped develop the field of electromagnetism by showing the interaction of electric and magnetic fields, after proving that a compass needle moves when exposed to a current. He inspired Ampere and Faraday.

Ampere (General Relativity)

Helped develop the field of electromagnetism by formulating the law of attraction and repulsion for currents.

Faraday (General Relativity)

Helped develop the field of electromagnetism by theorizing that charged objects create fields and that nearby objects feel their effects. He made many drawings of the visible fields. The ideas of Orstedt inspired him.

• He also discovered a transformer

Maxwell (General Relativity)

Helped develop the field of electromagnetism by taking Faraday’s theories and mathematizing them, as Faraday lacked that formal training. He tried to understand these fields through the conception of the ether and the mechanical model (honeycomb) of the ether.

• Honeycomb Ether: microscopic action of wobbling cells and idle wheels, which create the fields.

Electricity and Magnetism

From action at a distance to fields created by Maxwell as he combined the fields of electricity and magnetism. Maxwell’s calculations for the velocity of matter moving through the ether matched perfectly the speed of light measured in a laboratory earlier on.

• Light = Electromagnetic wave

Light (Optics)

From particles to (Newton) to waves (Young and Fresnel). A difficult transition until the early 1900s, with the dominance of Newton. These scientists hypothesized that light propagated in waves in the “luminiferous ether". This was very different than ordinary matter, similar to caloric or electricity. They championed the immobile ether (ether wind), but their adversary was the dragged ether.

Measuring the Speed of Light

The nail in the coffin for the particle theory, as Foucault and Fizeau found that the velocity of light in water is less than in air, aligning with the wave theory. This was a great advancement from astronomical observations of the speed of light.

Ether Drift Experiments by Michelson and Morley

Attempted to determine if the ether was dragged or immobile (wind) and concluded that the ether was dragged.

Hertz (General Relativity)

Helped develop the field of electromagnetism by generating electromagnetic waves and showing that they were light. He also harnessed radio waves, which was a huge advancement. He was integral in rephrasing the work of Maxwell for more to understand.

Lorentz (General Relativity)

Helped develop the field of general relativity with the responsibility of developing a theory that covered electromagnetism and optics. Developed the contraction hypothesis in response to the Michelson-Morley experiment, which was the basis for special relativity.

Einstein - (Special Relativity)

Developed the special theory of relativity for a new space-time structure. Published the paper “On the Electrodynamics of Moving Bodies” (1905), solving the issues of electromagnetism. He opened the paper by debunking the Lorentz theory with the magnet-conductor thought experiment. He includes postulates, such as the light postulate and the relativity postulate.

Minkowski (Space-time)

Einstein’s teacher, who developed the theory of general relativity with beautiful geometric interpretations of the 4D space-time. This is the form in which it is taught today. He created many Minkowski diagrams. This introduced a 4D curved geometry (introduced by Einstein) as opposed to special relativity’s flat geometry.

The Roles of Michelson, Lorentz, and Einstein in the Myth

The Myth: Spread by textbooks on how Einstein found special relativity, after the Michelson-Morley Experiment disproved the ether, two physicists created an ad hoc hypothesis, but then Einstein accepted the Michelson-Morley Experiment conclusion and based his hypothesis that light always has the same velocity on it.

• Michelson and Morley were testing whether an ether exists.

• Lorentz created a far-fetched hypothesis to sweep Michelson and Morley’s result under the rug and save his theory from being refuted.

• Einstein developed his theory of special relativity in direct response to the Michelson-Morley experiment.

Debunking Michelson in the Myth

Michelson and Morley were testing whether there exists an ether…No!

• They never questioned the existence of an ether, were only trying to discover whether the ether was dragged or immobile, and Michelson never accepted special relativity and clung to the existence of the ether.

Debunking Lorentz in the Myth

Lorentz created a far-fetched hypothesis to sweep Michelson and Morley’s result under the rug and save his theory from being refuted…No!

• The Lorentz-Fitzgerald contraction is a genuine physical effect which is even integrated into special relativity, Lorentz’s mature theory (corresponding states + generalized contraction hypothesis) predicts that no experiment will reveal motion with respect to the ether (special relativity → uniform motion), and he even paved the way for the abolition of the ether.

Debunking Einstein in the Myth

Einstein developed his theory of special relativity in direct response to the Michelson-Morley experiment…No!

• The Michelson-Morley experiment is not mentioned in Einstein’s 1905 paper explicitly, but he did know of the experiment and used it in support of special relativity, not the light postulate specifically.

• The simple conclusion of the Michelson-Morley Experiment is that the velocity of light depends on the velocity of the source, which entirely disagrees with the light postulate

  • Textbooks rephrased the light postulate as independent of the observer, not emitting body

Perpetuation of the Michelson-Morley Myth

It has an ideological appeal by reinforcing the picture of physics where experiment dictates theory (science stands up to authority). Einstein, specifically, didn’t agree with this and thought of theories as creations of the mind that can’t be derived, only supported or disproven from experiment. It also has a pedagogical appeal as it provides a simple way to introduce students to special relativity without electrodynamics.

How Special Relativity Actually Came About

Maxwell’s equations, which predict that light waves, assuming an at-rest ether, have a velocity independent of their source. Einstein assumed the ether prediction of these equations, but worried they would have to be changed in view of quantum phenomena.

Carnot (Thermodynamics)

He was envious of the Brits and aimed to study the efficiency of steam engines. He studied heat engines, developed Carnot cycles, hypothesized that no engine can be more efficient than a reversible one (perpetual motion of the first kind), and that heat from caloric (physical) can be transformed into a kind of motion (work).

• Believed that heat (caloric) is conserved, which is disproven by the second law.

Joule (Thermodynamics)

Develops a theory of motion creating heat to disprove Carnot’s assumption that heat was a substance, namely caloric, and that it was just another form of energy.

Kelvin and Clausius (Thermodynamics)

Created the second law of thermodynamics based on Carnot’s work, stating that it is impossible to move heat from cold to hot without doing work (Clausius), and it is impossible to 100% efficiently transfer heat into work (Kelvin). This negates the possibility of perpetual motion of the second time.

Maxwell (Kinetic Theory of Gases)

Working from the assumption that heat has a tendency to become less and less available for useful work, and a lack of irreversibility in this. With a system’s entropy leading towards more disorder and less usefulness.

• Kirchhoff: developed this theory from electromagnetism, in black body radiation, which would support quantum mechanics.

Boltzmann (Kinetic Theory of Gases)

Statistical nature of the second law of thermodynamics, helping to determine high-grade vs. (high entropy) low-grade energy, where the random motion of particles causes disorder in a system. Claiming that a system tends to become more disordered and tries to derive a formula, the H-Theorem, for the second law, proving the descent into equilibrium.

Gibbs

Extends the kinetic theory of gases into statistical mechanics, which is further developed by Planck and Ehrenfest.

Planck (Quantum Mechanics)

From trying to derive the second law of thermodynamics from electrodynamics to deriving a formula for black-body radiation, he connects the theories leading to special relativity with those leading to statistical mechanics. He believed there were no exceptions to the second law, latching on to the theory of Hertz resonators from electrodynamics. This was a flop as there is no reversibility, pointed out by Boltzmann.

• New method of applying heat theory to radiation

• Furthered black body radiation with Planck’s constant, the hallmark of quantum theory

Einstein (Quantum Mechanics)

Preceded by Ehrenfest, Einstein introduced light quanta, quantized matter, and is followed by the work of Bohr.

Bohr

“The reckless revolutionary.” After he finished his PhD in physics he went to the Cavendish with Thompson, then to Manchester with Rutherford.

First Solvay Conference (1911)

Present were Sommerfeld, Rutherford, and Planck. They discussed the formula for black-body radiation and analyzed plots for specific heats at low temperatures.

Rutherford

Came up with the basic idea for the planetary (nuclear) model of the atom, based on experiments bombarding atoms with alpha particles and analyzing the deflections.

Bohr

“On the Constitution of Atoms and Molecules” (1913) with a nucleus and electron, supported by spectroscopic evidence for it

• Explains regularities in the hydrogen spectrum

• Reactions: “less easy to accept that electrons emit no radiation” (Planck) and “a miracle…highest form of musicality in the sphere of thought” (Einstein)

Old Quantum Theory

Bohr and Sommerfeld, who aimed to determine all classically possible orbits using techniques of celestial mechanics, dealing with atoms like mini solar systems (Schwarzschild).

• They imposed quantum conditions to select a subset of those orbits allowed in quantum theory.

• Einstein altered this with electrons only in certain quantized energy states (not orbits) and light waves emitted in one direction.

• It eventually deteriorated as it only works for hydrogen like atoms and with the development of the dispersion theory (transition frequencies).

Heisenberg (New Quantum Mechanics)

Inspired by Kramers dispersion theory, as he was thinking of a theory in terms of transitions between orbits (ditching orbits themselves). He published his theory in “Quantum Theoretical Re-Interpretation of Kinematic and Mechanical Relations”, in terms of transition quantities, with two indices (initial and final), and represented by arrays of numbers.

• Matrix mechanics presented a new framework to represent physical quantities (special relativity → electrodynamics calling for a new framework by special relativity)

• His theory was further developed by Born (the three man paper)

Schrödinger

Evolved from Paris (23), where De Broglie proposed wave-particle duality for matter, explaining quantization of orbits in Bohr’s atom → Berlin (24), Einstein endorses this and derives mean-square fluctuation of energy and momentum in an ideal gas with Bose → Vienna (26), Schrödinger formulates the equation governing the behavior of De Broglie’s matter waves

• It discovered the particle behavior of matter as a wave, just as a wave phenomenon underlies geometrical optics.

Schrödinger vs. Heisenberg

Enemies, but their theories are two forms of the same theory (quantum mechanics)

Knabenphysik

Boys’ physics, full of young, bright scientists, Jordan, Pauli, and Heisenberg. They were taught by Sommerfeld (physics), Bohr (guru), and Born (math).

Lucy Mensing

Present at the creation of a new quantum mechanics with some valuable contributions, who outlived nearly all of them as well.

Röntgen

Discovered X-rays by working with Cathode rays (discovered at Cambridge by Thomson), as he noticed a screen lighting up as the cathode tube emitted a light that permeated through cardboard.

Becquerel, Marie, and Pierre Curie

Becquerel studied uranium salt and discovered that radiation has nothing to do with phosphorescence, and coined the term “Uranium/Becquerel rays.”

• Marie and Pierre Curie: find that thorium emits radioactive rays just like uranium, finds some samples of uranium are more radioactive than expected, and hypothesizes a more radioactive substance, polonium (3-400x), is present.

  • Polonium and Radium are similar to X-rays

Rutherford

Identified the three types of radioactivity: alpha (helium nucleus), beta (electron), and gamma (light quanta, gamma ray). In addition to this, with Marie, he discovers that radioactive decay leads to transmutation of elements and that non-radioactive elements can be transformed with alpha particles.

Nuclear Electrons

Initially hypothesized as having electrons and protons in the nucleus of an atom, but now the theory suggests the center of an atom is composed of neutrons and protons, and that the electrons orbit it (Bohr’s model).

Discovery of the Neutron

Chadwick, Frédéric Joliot, Irène Joliot-Curie

• Work by Bothe-Becker (Berlin 1931) and Joliot-Curie (Paris 1932) led Chadwick at Cambridge to conclude that beryllium bombarded with alpha particles emits neutrons (two years later it was recognized as a new elementary particle). Initially, it was thought that the neutrons produced were gamma rays.

• It is found that the mass of the neutron is greater than the mass of the proton plus the electron, solidifying the theory.

Artificial Radioactivity

Discovered by the Joliot-Curies

Fermi

His group in Rome suggests that bombardment with neutrons should be more effective in getting artificial radioactivity than alpha particles, and his crew bombards every element to test this. Discover that slow neutrons are much more effective in getting nuclear reactions.

• 1922: Mussolini rules fascist Italy

• 1937-38: Group disbands

Hahn and Meitner (f)

Their group in Berlin did experiments to understand Fermi’s production of transuranic elements. They discover that instead of transuranic elements, radium and two alpha particles are produced.

• 1938: Nazi’s rise to power and Meitner flees from Germany to Sweden. Hahn writes her a letter, stating that barium is produced during uranium bombardment. Meitner and Frisch meet for breakfast to discuss these results.

Discovery of fission

Hahn, Meitner, and Frisch discovered that the neutron infiltrates the uranium nucleus and may cause the nucleus to elongate and break into two.

• Liquid drop model

Liquid Drop Model of the Nucleus

Berlin (Meitner) focuses on calculating the energy per nucleon (protons and neutrons) against atomic weight. Whereas Copenhagen (Frisch) focuses on figuring out the mechanisms of radioactive decay of a nucleus modeled as a drop of water.

Oppenheimer - Early Life

Born in 1904 to upper-class Jewish immigrants, Robert would attend an ethical culture school run by his family, suffer a humiliating experience with green paint, and be kind of ambivalent about his Jewishness, as pointed out by fellow scientist and close friend Rabi.

• Education: Harvard [Bridgman], Cambridge [Blackett, poisoned apple], Göttingen [Born], and had professorial appointments in Berkeley and Caltech.

Lawrence

The Midwestern Lutheran experimentalist, inventor of the cyclone, and close colleague to Oppenheimer at Berkley. He ran the Rad Lab on the West Coast, where they conducted bomb research.

Quantum Mechanics in the US

As a professor, Oppenheimer created his own school of theoretical physics at Berkley where he spread the gospel of quantum mechanics. Other physicists, Van Vleck and Slater, were also teaching quantum mechanics. They differed from Oppenheimer as they were solid-state physicists, not nuclear, and worked on radar rather than the atomic bomb.

• Nuclear physics was much more prestigious after the war.

• Van Vleck + Slater: Students Bardeen, Brattain, and Shockley invented the transistor in 1947.

Solid State vs. Nuclear Physics

Atomic bomb (West Coast) vs. Radar (East Coast)

Jean Tatlock

A woman with communist ties who became close to Oppenheimer. She undoubtedly influenced his left-wandering tendencies. Their relationship broke off in 1939, but Oppenheimer visited her a few more times after that, breaking security and marital vows. Jean committed suicide the day after their last visit.

• Oppenheimer cheats with Jean on his wife, Kitty, who also has communist history.

Szilard and Einstein’s letter to Roosevelt

On August 2, 1939, Szilard helped Einstein draft his letter to Roosevelt, and it was delivered in October of that year. It warned of the Germans’ progress in developing a nuclear bomb, and an advisory committee on Uranium was appointed.

• The committee’s top advisors were Bush and Conant

Fission and the Atomic Bomb Frenzy

Spurred by Rosenfeld's alerting Princeton about fission. Others, like Fermi, started working on fission to create a chain reaction and then developed an atomic bomb (U-235/238 at UMN by Al Neir). Hitler then invaded Poland, as the Bohr-Wheeler paper on nuclear fission was published, a publication hold on this topic followed quickly, lobbied for by Szilard.

Frisch-Peierls Memorandum

Follows the exploration of nuclear fission, experimentation with uranium, and the discovery of plutonium. It discusses the feasibility of the atomic bomb, claiming that the critical amount of U2235 would be about one pound.

• The MAUD committee is then formed, and the conclusion in the summer of 1941 was that it was feasible, but too ambitious for Britain alone.

Pearl Harbor

December 7, 1941 → The catalyst for the rapid expansion of the efforts to develop the atomic bomb

Manhattan Project

The project of co-operation between scientists and the government had three locations: Oak Ridge, where U235 was separated from U238; Hanford, where plutonium was generated; and Los Alamos, where construction and testing of the bomb took place, also where Oppenheimer and other notable scientists were stationed.

General Groves

He established the “Manhattan Engineer District” at the request of the government and oversaw the operations. He then recruited (with Nichols) Oppenheimer for the Manhattan Project in 1942. They knew of Oppenheimers communist ties and either didn’t care because he was so talented or because they could use that to manipulate him.

Moral Qualms

The Manhattan Project got started for fear of the Germans getting there first, but it became clear this wouldn’t happen and that the Germans were losing the war. Yet, only Joseph Rotblat left the project (and later won the 1995 Nobel Peace Prize).

• Other Doubters: Robert Wilson organizes a meeting discussing why the project continued despite the war basically being won. (Oppenheimer attends a meeting and convinces many that the war would not be won without the atomic bomb, “Theory will only take you so far.”)

• Spy for the Soviets: Klaus Fuchs

Trinity Test (July, 1945)

Nuclear test with a massive explosion → “Now I am become death, the destroyer of worlds,” said Oppenheimer, “I think we just said it worked,” said Frank, and “Now we’re all sons of bitches” said Bainbridge.

Yalta and Potsdam conferences

The Yalta conference took place between Churchill, FDR, and Stalin in February 1945. The Potsdam conference occurred between Attlee, Truman, and Stalin the day after the Trinity Test.

Bohr Doctrine (Oppenheimer)

The bomb to end all wars, figured that no war would occur after the destruction that the atomic bomb would cause was witnessed by mankind. Teller responded to this by saying “until someone builds a bigger bomb”.

Hiroshima and Nagasaki Decision

The decision to drop the bomb was influenced by Oppenheimer’s refusal to back the ‘Franck report’ calling for demonstration rather than combat use. He met Szilard, who supported the report before the discussion, and implied they might not use it. In the meeting, Oppenheimer presents his talking points, but ultimately has no sway on the direction of the conversation.

• 1. The bomb to end all war

• 2. Notifying the Soviets

• 3. Relaying concerns of fellow scientists, but in such a tepid way that he’s easily shut up

Hiroshima and Nagasaki Result

They decide to drop the bomb, claiming that it will save American and Japanese lives. On August 6 and then 9, 1945, “Little Boy” was dropped on Hiroshima, and then “Fat Man” was dropped on Nagasaki. They killed tens of thousands and wounded comparable amounts.

Blackett’s “not the last act of WWII but the first of the Cold War”

The Soviet Union would have and did declare war on Japan by August 15 (happened August 8th), which would have rendered the use of the atomic bomb unnecessary, as Japan would’ve surrendered. The US wanted Japan to surrender to them alone, this is the beginning move of the Cold War.

Oppenheimer’s Audience with Truman

Oppenheimer states that there is “blood on my hands,” and Truman responds that the Soviets will never have a bomb…Wrong!

Acheson-Lilienthal Plan

Largely Oppenheimer’s, created for the call for an international organization to regulate atomic energy from the US, UK, and Canada. The United Nations Atomic Energy Commission (UNAEC) then revised the Acheson-Lilienthal plan, which the Soviet Union rejected, a missed opportunity for arms control. The Cold War is now on and Truman establishes the AEC.

McMahon Act

The Atomic Energy Act, which transferred control over nuclear power from military to civilian authorities. He was a strong opposition to Oppenheimer and disagreed about the H-bomb and arms control initiatives.

• Lilenthal becomes the chairman of the Atomic Energy Commission (AEC), and Oppenheimer the chair of the General Advisory Committee (GAC) after undergoing a security review.

HUAC

Oppenheimer testifies in front of the House Un-American Activities Committee and throws four of his students under the bus as communists, as he thought the transcripts would be private. He apologizes for this later, but it still has dire effects for those involved. He most likely did this to protect his brother, who testified 7 days later, but lost his job at UMN and had to move anyway.

Edward Teller

A large proponent for the H-bomb, which was opposed by the GAC and AEC as it was irrelevant and would only fuel an arms race. Truman still announces the H-bomb development anyway.

Oppenheimer’s Ties to Communism

Girlfriend Tatlock, wife Kitty, brother Frank, Chevalier incident, role of Pash are all analyzed during the 1954 hearing. Specifically, the Chevalier incident, where Oppenheimer is told of Eltenton asking Chevalier for secrets to share with the Soviets. Oppenheimer doesn’t report this for several months in an interview with Pash, where he gives all names except for Chevaliers, which he later shares with Lansdale as a direct order from Groves. This comes back to haunt him (Groves too) as his words are held against him and he is painted as a lair when asked to recall what he said to Pash.

Strauss

Appointed chairman of the AEC by Eisenhower. He uses Nichols and Borden as his henchmen to put a stop to Oppenheimer because of his personal animosity, H-bomb disagreement, and arms talks disagreement.

• “We’re not convicting just denying”

1954 Security Hearing

The hearing for Oppenheimer’s clearance → Robb vs. Garrison, deck stacked against Oppenheimer…It takes place in front of the three-person Gray board. Teller’s testimony is the most detrimental, as he doesn’t like Oppenheimer based on H-bomb disagreements, and testifies that he doesn’t doubt Oppenheimer’s loyalty but his intelligence on whats best for the US. This gives the AEC committee the idea to revoke his clearance, but claim he is still loyal, a conclusion that is made more negative at the final board with Strauss and Nichols input.

Fermi Award

In 1963, Oppenheimer received the Fermi award after being nominated by Teller. This aligns with Einstein’s experiences and predictions, where “that award wasn’t for me. It was for all of you…Now it is your turn to deal with the consequences of your achievements. And one day ... they’ll ... give you a medal ...”

Start of Nazi Regime

Germany was under Nazi rule in the 1930s, and civil service laws hit the physics community hard. Professors are now expected to sign an oath of allegiance to Hitler, attend indoctrination camps, begin public lectures with a Nazi salute, and sign all official correspondence with “Heil Hitler”.

Heisenberg in the 1930s

Succeeds his teacher Sommerfeld in 1935, but was attacked as a “White Jew.” During this, he meets his wife and has kids, and his reputation is preserved by Himmler. He decides to stay in Germany to preserve German physics after the Third Reich. He is recruited to the Uranium club, Uranverein (German bomb project), by Diebner, along with Weizsäcker and Hahn.

Heisenberg vs. Diebner

Diebner, an explosives expert, who was a less prestigious but more practical Nazi supporter, competed with Heisenberg, a more prestigious Nazi skeptic. During the project, Heisenberg becomes a professor in Berlin, until its bombing, when he then moves his team south.

Alsos mission

After the defeat of Germany in 1945, Gouldsmit and Pash were sent to look for Von Weisacker’s paper. They then capture Hahn and Heisenberg. These two, along with Weizsacker, are held at Farm Hall, where they are observed, and their conversations are listened to.

Von Weizsäcker’s Excuses

For the failed German bomb project…

• “All the physicists didn’t want to do it, on principle. If we had all wanted Germany to win the war, we would have succeeded.”

• “The peaceful development of the uranium engine was made in Germany; Americans developed the ghastly weapon of war.”

Debate of Heisenberg’s role

Lots of literature has been written discussing whether he was incompetent and actually wanted to develop a bomb, or if he was just dragging his feet. Frayn’s play Copenhagen is a dramatized version of the 1941 meeting with Bohr. Bohr claimed that Heisenberg and Weizsäcker were adamant on Germany’s future success in building the atomic bomb and were doing everything to achieve that. (Grey areas)

General Myths About Einstein

That his letter to FDR started the Manhattan Project, he was a poor student, his first wife discovered special relativity, and Einstein was born at the age of 50. He also had bad relationships, with tensions peaking during the start of WW1 and his friendship with a Nazi scientist.

1933 Spencer Lecture + Einstein

He believed that nature could be derived from math and that “the creative principle resides in mathematics.” Initially, though, Einstein thought that an empirically adequate concotion does not a satisfactory theory make! Stating that “to find out anything from the theoretical physicist…do not listen to their words, fix your attention on their deeds.”

Principle vs. Constructive Theories

Constrictive Theories (preferred): start with a model of the relevant features of the physical world.

Principle Theories (mastered): start with experimentally well-confirmed regularities, a physics of desperation by limiting oneself to finding constraints on semi-satisfactory constructive models.

• “The more and more I tried, the more I came to the conviction that only the discovery of a universal formal principle could lead us to assured results.”

Einstein - Developing Theories

He uses inductive generalizations (Humdrum), exploits explanatory deficiencies in existing theories (Magic Wand 1 for special and general relativity), and exploits the violent clash of different parts of existing theories (Magic Wand 2 for light quantum).

• Magic Wand 1: Lorentz's failure to explain the magnet and conductor phenomenon, and the equivalence paper of general relativity.

The home stretch in formulating general relativity, unifying inertia and gravity into one inertio-gravitiational field, was almost achieved first by Hilbert, who solely used math, influencing Einstein to adopt that same strategy.

“Beyond the merely personal”

How Einstein viewed physics, where he could use it to escape the dreariness of personal life. Especially when Einstein is in crisis, he really leans into this and exaggerates it in retrospect.

• During this shift, he is described as “something incomprehensible in its absence of emotion.”

Lecture in 1914 vs.1918

Inaugural lecture in 1914 (before separation, illness, war): “Scientists deduce principles from nature by perceiving complexes of empirical facts, general features for precise formulation.” Some theories are too narrow, even if they agree with the data…the opposite of the 1933 Spencer lecture promoting pure math.

Lecture for Planck’s 60th birthday in 1918 (after separation, illness, war): “I believe with Schopenhauer the strongest motive to escape into science is to get away from personal life into objective perception…to find peace and security.”

Einstein - Tumultuous Relationships

Einstein was somewhat of a womanizer and wasn’t very kind to his wives. (Possible #MeToo offender)

Mileva Marić: His first wife, who was a fellow student. They had three children, Lieserl, who we have no trace of and was conceived out of wedlock, Eduard, and Hans. They stayed married as long as she completed her housewife duties, didn’t interact with him, and were essentially hostile roommates until they separated.

Elsa Einstein: His second wife and cousin, with whom he was having an affair.

Reading of Schopenhauer

Einstein’s reading of Schopenhauer played a role in his shift from putting the facts first (empiricism - constructive) to putting math first (rationalism - principle). Schopenhauer’s romantic ideas led Einstein to never do anything important in physics again, by building mathematical castles in the sky.

Einstein’s Critique of Quantum Mechanics

The probability that a banana tastes yummy out of two bananas is 1/2. If you taste banana #1 and it tastes yummy, then you know banana #2 will be yucky…but was it determined before you tasted banana #2 that banana #1 would taste yummy? The quantum theory would say no, but Einstein would say yes and that the probability description is incomplete. Einstein thought that if Quantum Mechanics were correct, we would have “spooky action at a distance”, as the correlation would exist no matter how far apart they are.

Einstein-Podolsky-Rosen (EPR) Paper

Einstein’s most cited paper, which was viewed at the time as him losing touch with modern physics, was actually the beginning of the enlightenment at the heart of modern quantum cryptography and computing (always A+B). Predictions were incorrect, but inspired new thinking about quantum systems.

• QM states we cannot know two measurements (position and velocity) of any one particle at the same time according to Heisenberg’s uncertainty principle. Einstein feels that these metrics are determined by hidden variables that are not part of the quantum description.

Hidden Variables

Einstein’s suggestion that QM is incomplete and that there are hidden variables, which was tested in the ‘spin’ experiments (peeling → tasting experiment). They conclude that the quantum mechanics predictions are correct.

Entanglement

In a compound system with parts A and B, in quantum mechanics, their states are inextricably entwined or “entangled”, according to Schrödinger. This results in a strong correlation between measurements of these two components that cannot be explained by classical physics.

Heisenberg’s Uncertainty Principle

States that it is fundamentally impossible to know both the exact position (x) and momentum (p) of a quantum particle simultaneously.

Schrödinger’s Cat

The microworld behaves differently from the macroworld, with the issue that quantum behavior at the microlevel has a tendency to spread to the macrolevel. Represented with the possibly poisonous flask (decayed or non-decayed atoms) and a cat.

Copenhagen Interpretation

With Schrodinger’s cat, if you open the box, you have a 50/50 chance of finding a live or dead cat.

Mermin’s Slogan

‘Shut up and calculate’…1950’s culture and attitude surrounding physics, where interpretation was pushed to the side. This is overcome as the physics community now promotes work in foundations of quantum mechanics following various different approaches (Copenhagen make-overs, Everett, GRW, QBism, Bohm, ...).

Everett’s Many-Worlds Interpretation

A view that descends from the Copenhagen crowd, with two worlds in which the cat is dead, and the other where the cat is alive. So every time you make a measurement, the world splits into several worlds, one for each possible outcome. The observer then becomes involved in whether they see a dead or alive cat, not so definite anymore.