Understanding the Quantum World

Focusing on the behavior of quantum entities as both particles and waves; the approach of presenting analogies over equations, Professor Carlson gives a handy way of visualizing this paradox; using a slinky to show how waves can be quantized.

The double-slit experiment; electrons behave as both particles and waves when passing through two parallel slits in a plate and then striking a screen; the wave properties disappear when the electrons are monitored as they pass through each slit.

If quantum effects hold at one's everyday scale; there would be no trouble sitting in three chairs; what happens when a particle in such a mixed state is forced by measurement to assume a definite position; observers disturb what they measure.

Two responses to the apparent incompatibility of quantum mechanics and classical physics; Bell's theorem shows that attempts to reconcile the two systems are futile in a certain class of theories; Schrodinger's cat is a thought experiment.

The major theories to explain the paradoxes of the quantum world; the Copenhagen interpretation; Einstein's realist view; the many worlds interpretation; quantum Bayesianism; non-local hidden variables; what seems to be governed by probability alone.

Heisenberg's uncertainty principle sets a limit on how much one can know about an object's position and momentum at the same time; Professor Carlson shows why atoms have structure and come in the diverse forms of the periodic table of elements.

Electrons don't just orbit the nucleus; they simultaneously exist as standing waves; learning what standing wave modes look like in one, two and three dimensions; these shapes explain the quantization of energy states in an atom; useful analogies.

Standing waves of electrons around nuclei; the periodic table of elements results from what electrons do naturally; falling into the lowest energy state given the total electric charge and existing electron population; the Pauli exclusion principle.

Learning what happens when electrons are put into waveforms that differ from standing waves; some of these superposition states are unstable; the sloshing of an electron back and forth in an unstable state causes it to act as an antenna.

Knowing the dramatic difference between diamond and graphene; both are composed of pure carbon; the role of electrons in molecular bonds; applying knowledge of electron standing waves; in carbon, such waves make possible several types of bonds.

A clock pendulum is an example of a classical harmonic oscillator; how quantum waves behave like harmonic oscillators; quantum physics is born at the turn of the 20th century; Planck states that the energies of oscillation have to be quantized.

The Heisenberg uncertainty principle; how quantum uncertainty extends to energy and time; this has an implication for energy conservation; short-lived particles can pop into existence out of nothing; evidence in the Lamb shift and Casimir effect.

Probing the counterintuitive quantum world by contrasting angular momentum for planets with analogous phenomena in quantum particles; the Stern-Gerlach experiment; it shows that spin is quantized for atoms; a limited number of discrete values.

Turning to orbital angular momentum; a phenomenon familiar in classical physics relating to planets has an analogue in the quantum domain; Professor Carlson calls permanent magnets "a piece of quantum physics that you can hold in your hand".

Einstein states that light comes in discrete packets of energy called photons; the photoelectric effect prompts Einstein's discovery; demonstrating the effect; surveying applications of the quantum theory of light to phenomena such as lasers.

The interactions of light with matter; the changes in energy and angular momentum when an electron transitions from one orbital to another; the diverse possibilities create a fingerprint specific to eveary type of atom; the basis for spectroscopy.

The structure of a cesium atom; what makes it ideal for measuring a second's length; serving as the basis for atomic clocks; how GPS satellites use atomic clocks to triangulate positions on the ground; Einstein's theories of relativity.

The quantum events that underlie color vision; the role of the retinal molecule in detecting different frequencies of photons; the source of color blindness; its inverse, tetrachromacy is the ability to see an extra channel of color information.

The sources of color in the world; grasping the secret of the aurora; the difference between fluorescence and phosphorescence; the reason neon dyes look brighter than their surroundings; one's experience of color is governed by the quantum world.

Anyone who uses a memory stick relies on quantum tunneling, a baffling aspect of the quantum world; Professor Carlson uses a roller coaster analogy, combined with one's insight into wave mechanics; making the feat of quantum sorcery logical.

Probing why two pieces of matter cannot occupy the same space at the same time; the other class of particles, bosons, with integer spin, can be in the same place at the same time; this feature of bosons is exploited in lasers and in superfluids.

The challenge to the Copenhagen interpretation of quantum mechanics; the paradox proposed by Albert Einstein and his associates; whether quantum mechanics is an incomplete theory due to hidden variables that guide the result of quantum interactions.

Analyzing how metals conduct electricity; electrons surf from one metal atom to the next on a quantum mechanical wave; the causes of electrical resistance; why metals can never be perfect conductors; applying the Pauli exclusion principle.

Professor Carlson closes with superconductivity; while electrons lose energy to resistance when they flow through a metal, this is not true of superconductors; quantum stability allows superconductors to conduct electricity with zero resistance.