Quantum Physics: an overview of a weird world
4.6 (296 ratings)
Course Ratings are calculated from individual students’ ratings and a variety of other signals, like age of rating and reliability, to ensure that they reflect course quality fairly and accurately.
4,482 students enrolled

Quantum Physics: an overview of a weird world

A primer on the conceptual foundations of Quantum Physics
4.6 (296 ratings)
Course Ratings are calculated from individual students’ ratings and a variety of other signals, like age of rating and reliability, to ensure that they reflect course quality fairly and accurately.
4,482 students enrolled
Created by Marco Masi
Last updated 7/2018
English [Auto-generated]
Current price: $9.99 Original price: $19.99 Discount: 50% off
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This course includes
  • 15.5 hours on-demand video
  • Full lifetime access
  • Access on mobile and TV
  • Assignments
  • Certificate of Completion
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What you'll learn
  • The conceptual foundations of Quantum Physics that nowhere else are taught.
  • The course does not need any mathematical skills.

Note: Take a look at the free lectures! Scroll down to the curriculum and click on 'Basics I'. The 'preview' lectures are free. That might help you to get a better feeling on what's about.

Why this course? This is a course that originates from my desire to share my knowledge of the mysterious as fascinating world of Quantum Physics. Considering how the media (sometimes also physicists) present Quantum Theory focusing only on highly dubious ideas and speculations backed by no evidence or, worse, promote pseudo-scientific hypes that fall regularly into and out of fashion, I felt it necessary to create a serious introduction to the conceptual foundations of Quantum Physics for all. The world needs to know what Quantum Mechanics is, as it really is, beyond vulgarized oversimplifications which have led only to misunderstandings. This is also a long-term project, which aims at demystifying quantum physics. An extended and detailed treatise that aims at rising the global awareness on a subject I love to talk about. I have worked hard to create not just a “quantum physics for dummies” course but a a high level and professional account which remains nevertheless accessible to all. I sincerely hope you will enjoy it and that it will make you discover new realities. I will continue to work on it. You can help by enrolling.

Who is it for? This course is for all and does not need any technical background. It is for those who always wanted to understand the principles of quantum physics, even if they are not physicists. For those who always have been attracted by the fascinating and weird quantum world, but found only advanced level university courses, or superficial popular science accounts or, worse, pseudo-scientific theories. For those who searched for a course that explains the basics of the conceptual foundations of Quantum Mechanics, but that does not presuppose a technical preparation, and yet furnishes the most rigorous and advanced account as far an (almost) non-mathematical exposition allows for.

Since in schools, colleges and universities, Quantum Physics is taught with a dry and almost exclusively technical approach which furnishes only a superficial insight on its foundations, this course is recommended also to school, undergraduate and graduate students who would like to look further. Not only physicists could (re-)discover some topics but philosophers and historians of science could acquire with this course a basic preparation which is unlikely to be offered in most departments. This online course proposes itself also to become part of a faculty curriculum in departments or other institutions which would like to expand their interests towards the foundations of Quantum Physics (contact the instructor for details).

What is it about? A course on the conceptual foundations of Quantum Physics on topics that you won't find elsewhere explained at introductory level, designed to be a comprehensive A-Z guide that will save you a ton of time in searching elsewhere trying to piece all the different information together. It will lead you by hand as clearly as possible from the abc of Quantum Mechanics to the most recent experiments and its implications.

A course that does not only introduce you to the basics of quantum theory, but covers also with a simple approach topics and several experiments that usually are discussed only among specialists. We review the standard concepts like the wave-particle duality, Heisenberg`s uncertainty principle, Schrödinger`s cat, the vacuum zero-point energy and virtual particles, among several others. Then we deepen the subject analysing quantum entanglement, the so called "EPR paradox" which question our naive understanding of the meaning of reality and locality, together with other effects and ground breaking discoveries of the last century physics. Another, more advanced section, and that is usually not explained to the popular audience in an accurate but clear and understandable way, is what I call the "quantum ontology experiments", like the "which way", "quantum erasure", "delayed choice", "interaction free" and "quantum teleportation" experiments. This course is unique in the sense that, after delivering a historic introduction and the foundations, it discusses also several topics which go to the essence of the quantum phenomena, making it available for the first time in an easy understandable way to everyone. Especially the part on the quantum ontology experiments may be interesting for physicists who want to deepen their conceptual foundations.

My aim is to deliver the material necessary so that you will be able by yourself to distinguish between mere speculative (and more or less extravagant) interpretations in fashion, and the real Quantum Theory and its experimental facts as it is.

Note: Those living in countries with the PPP ranking below 50 (see the list of countries by GDP (PPP) per capita on Wikipedia) will get a $9.99 special offer coupon. Send an id to marco.masi@gmail.com  - School, college or university students will get a free coupon. Send an e-mail from your school/department account (or the scan of an id) to marco.masi@gmail.com and you will get the coupon.

Who this course is for:
  • Everyone who is passionate about science and/or philosophy of science and is curious about the laws and the nature of the material universe.
  • The course is well suited for all those university students who do not have sufficient mathematical background to go through a high-level QM course, but would like to assimilate the basics of quantum physics for the purpose of additional research. For instance philosophers, historians of science or biologist.
Course content
Expand all 46 lectures 15:35:06
+ Introduction to the course
1 lecture 24:46

Some preliminary comments about the aim, idea, structure and content of the course and how it distinguishes itself from other courses on Quantum Physics.

Preview 24:46
+ Basics I - The birth and foundations of quantum mechanics
16 lectures 05:43:14

Some few historic remarks on how the nature of light was understood from the ancient Greece to Thomas Young's double slit experiment.

Preview 10:19

Introduction to the concept of force field and the interference of waves.

Preview 15:44

This lecture describes the famous double slit experiment of Thomas Young. It is one of the most classical experiments which suggest the wave-like nature of light and which remains until nowadays the paradigm experiment of Quantum Physics.

Young's Double Slit Experiment

Before 1905, according to classical physics every material object that is not frozen to the absolute zero temperature should emit an infinite amount of energy. Here we describe why inside classical physics this paradox could not find a resolution.

The Blackbody Radiation before Max Planck

The historical point of departure of quantum theory was Planck's derivation of the black body radiation which assumed energy to be quantized. Previously it was thought that energy is a continuous phenomenon. Its quantization was a conceptual revolution that can be compared to a sort of "Copernican revolution".

The Blackbody Radiation after Max Planck
The course is going to be replaced from the first to last lecture. This assignment covers only lectures 1-6. Every time a new lecture is uploaded new questions and answers to check yourself will be added as well. You will be informed through the announcements emails (set it on in your settings).
Check your understanding (lecture 1-6)
11 questions

The photoelectric effect comes as a further validation of the fact that energy appears always quantized. The photoelectric effect was explained by Einstein introducing the notion of the light particle, the "photon".

The Photoelectric effect

Bohr, inspired by the result of the photoelectric effect, advances his famous "planetary model" of the atom. 

Bohr's atomic model

Bohr's atom model seemed to receive experimental validation by Frank-Hertz's experiment which definitely demonstrated that atoms absorb energy in quantized amounts of energy. 

The Franck-Hertz experiment

The Compton scattering of photons and showed further that electromagnetic radiation has also a corpuscular nature.

The Compton effect

Pair creation and annihilation shows how matter and anti-matter particles can transform in pure energy and back. It is another example that showed that electromagnetic radiation has a corpuscular nature.

Pair creation and annihilation
Q&A on the lectures to test yourself
Check your understanding (lecture 7-11)
9 questions

Bragg diffraction and the de Broglie hypothesis pave the way for understanding better the wave-particle duality problem.

Waves strike back: Bragg diffraction and the de Broglie hypothesis

Are photons and electrons particles or waves? If they are both, when do they show upn as one or the other aspect? The wave-particle duality illustrated by Young's double slit experiment will shed some light on this.

Preview 36:27

Heisenberg's uncertainty principle is explained and some of its frequent misinterpretations illustrated.

The Heisenberg's uncertainty principle
Q&A on the lectures to test yourself
Check your understanding (lecture 12-14)
5 questions

The concept of the wavefunction in quantum mechanics is explained. We will address the question if the wavefunction is a mere mathematical object or if it represents a real physical entity.

The wavefunction and the measurement problem

The description of the quantum world in terms of a probabilistic interpretation led to a mathematical formalism which is quite different than that used in classical physics. Classical states and dynamical variables are replaced by state vectors and operators, the "observables". The resulting formalism led to Schrödinger's equation which became the base for a successful understanding of atomic physics.

The state vector, observables and the Schrödinger equation

The modern concept of the structure of atoms in quantum mechanical terms relies on a probabilistic description. Electrons around the atomic nucleus have no longer defined positions or orbits but must be described by probability distributions, the atomic orbitals.

Atomic orbitals
Q&A on the lectures to test yourself
Check your understanding (lecture 12-17)
5 questions
+ Basics II - Mysteries and paradoxes of the quantum world
13 lectures 04:26:55

Angular momentum and spin are physical quantities which we intuitively ascribe to rotating objects. Do they apply in the same way for elementary point particles?

Spin: do particles rotate?

The Stern-Gerlach experiment was decisive in demonstrating the impossibility to know the particles's spin values along two directions at the same time.

The Stern-Gerlach experiment and commutation relations

Can particles spin clockwise AND anti-clockwise at the same time? In the microscopic quantum world it is a normal state of affairs.

Quantum superposition: being in two states at the same time

Can a cat be dead AND alive at the same time? Quantum mechanics seems to suggest this, however at a closer inspection the paradox can be solved.

Schrödinger`s cat: ``dead or alive´´, or ´´dead and alive´´?

In analogy to Heisenberg's uncertainty over position and impulse, likewise it is impossible to determine with absolute precision the energy has at a definite time. There are however fundamental differences between the two uncertainties.

The time-energy uncertainty

Can a particle jump through a classically forbidden barrier? Quantum mechanics allows to tunnel through a potential barrier even if it has not the classical allowed energy to do that.

The tunnel effect: jumping over forbidden barriers

Is "empty" space really empty? According to quantum physics there can't exist no such thing. We will take a look at the vacuum zero-point energy, the concept of virtual particles and the Casimir effect.

Vacuum zero-point energy, virtual particles and the Casimir effect

Enstein and Bohr did not agree on how to interpret quantum physics. Einstein tried to disprove it with thought experiments and Bohr pointed out its fallacies. The Copenhagen interpretation of quantum mechanics took shape.

The Einstein vs. Bohr debate

Two identical elementary particles are no longer distinguishable after interaction. They will form a unique indistinguishable whole.

Quantum indistinguishability

In quantum theory particles can be entangled with each others also light years away and apparently "feel" instantly the state of the other. How should this be correctly interpreted?

Quantum entanglement

A. Einstein, B. Podolsky and N. Rosen proposed a thought experiment that was supposed to show how it is possible to circumvent the commutation relations of QM and why it has to be considered therefore an incomplete theory. Were they right?

The EPR paradox

Some quantum phenomena seem to imply an action at a distance faster than light. Instant correlation between particles also light years apart are possible. Does this allow for faster than light transmission of information?

Faster than light transmission?

It looks like that quantum mechanics describes a non-local reality, where apparently faster than light interactions might occur. In what sense should we interpret this? What experiments could help us to discriminate between different interpretations?

EPR's legacy and Bell inequalities: what is a local reality?
+ Supplemental I - Going deeper into the quantum realm
7 lectures 02:04:20

What does it really mean that particles interact? What is a field and what kind of particles are the "material" particles and those responsible as force carriers? This lecture sets the stage to understand better the distinction between bosons and fermions.

Bosons, fermions and the Pauli exclusion principle: part I

The universe is made by two types of particles: bosons and fermions. In this lecture we review the basic properties of them and how they behave differently in quantum mechanics.

Bosons, fermions and the Pauli exclusion principle: part II

The Pauli exclusion principle, one of the most fundamental principles of quantum physics, is explained, and its consequences or the behavior of matter in extreme conditions like in White Dwarfs or neutron stars analysed.

Bosons, fermions and the Pauli exclusion principle: part III

Why is matter stable? Why do electrons not fall into the atomic nucleus?

The stability of matter

This is a long lecture and for advanced students only. It is however not compulsory or necessary to understand the rest of the course material. It is nevertheless a fascinating effect which shows how quantum objects do (apparently?) not need to be in direct contact with a magnetic field to be influenced by its presence.

The Aharonov-Bohm effect

The Quantum Zeno effect is a strange quantum property of the quantum world whereby, the time evolution of a quantum system can be suppressed by frequent measurements.

The quantum Zeno effect

Why do particles, which are not subjected to external forces, move along a straight line? Richard's Feynman path integral formulation of quantum mechanics furnishes an unexpected answer.

Path integrals and Feynman diagrams
+ Supplemental II - Quantum philosophy reborn
7 lectures 02:06:10

With the advent of laser and optical technologies it is nowadays possible to perform experiments which were impossible at the times of Einstein or Schrödinger. The Mach-Zehnder interferometer is a typical device that is used to test the foundation of quantum mechanics and is worth a closer look.

The Mach-Zehnder interferometer

The "which way" experiments are particular experimental setups that trace the whereabouts of a particle without perturbing it along the path, and which show that the mere information of the particle's path is sufficient to destroy interference.

"Which Way" experiments

Please consider that the second polarzation-rotator should be placed after the first polarization-rotator and before the second beam splitter (i.e., NOT after the second beam splitter and D1, as shown in the lecture's slide). I  apologize for this mistake and will fix this with a new video as soon as I can, but meanwhile keep this in mind!

It is information about the path a particles travels along which makes the wavefunction collapse. But is it due to a perturbation of it or is it a general (information theoretic) law of nature? By using twice the same device which furnishes this information, but erasing it at the second stage of measurement we get the answer.

Quantum erasure experiments: is information physical?

Is it possible to measure the presence of an object without interacting with it? Does meausurement always imply interaction and perturbation of the measured object?

Interaction free experiments: how to detect a bomb without interacting with it

Can we deceive nature by delaying the choice if we want to observe the wave or particle nature of a photon flying through the double slit experiment?

The "delayed choice" experiments: trying to deceive nature

The Scully-Englert-Walther experiments contains several of the typical quantum philosophy experiment: it is a quantum eraser and which-way experiment that shows the wave-particle duality for atoms. It is important for understanding how the principle of complementarity is fundamental and seems to have temporal retro-causal effects.

The Scully-Englert-Walther experiment and the complementary principle

Quantum teleportation is a bizarre quantum effect that reminds scifi transportation systems like that of the "beaming" of objects in Star Trek's film. This is still not possible for macroscopic objects, but it has been shown experimentally to be possible with single particles or atoms.

Quantum teleportation
+ Conclusion
1 lecture 03:50
Final considerations and outlook
+ Appendix
1 lecture 45:51

Some elements, especially of complex numbers and functions, is explained. The lecture is useful for those who are not acquainted with principles of analysis, but can be skipped by those who are.

Appendix: a short mathematical primer