*(Merci de cliquer sur le drapeau français sur la bande de gauche pour voir ce texte en français)*

In this series of videos we will “resolve” *some* of the supposed “mysteries” in Quantum Physics and Relativity (Wave/particle duality, Schrödinger’s cat, Constant Speed of Light, Paradoxes in Relativity, etc.).

The first 7 videos are with (almost) no maths (and dubbed in French on this page..). The rest are videos which get into the details by explaining why certain math tools are used for these topics, and explain more thoroughly why they can help solve some of the “mysteries” in Q.P. and R.

I recommend that you view all the videos in the right order, as we will introduce some concepts that we will use later in the series.

Note that these videos are also available on Youtube. The advantage of playing videos from this web site is that there are no ads… Plus, on this page, the first 7 videos are dubbed **in French** !

Finally I apologize if you find the videos too provocative, in particular to physicists… Please take my comments with a grain of salt…

**The First Seven (in French!): Solving “mysteries” in Quantum Physics and Relativity with (almost) no maths**.

**Preliminaries (part 1): The 3-World Concept**

This video is the first one in the series, so it may be the most important one to understand the rest of the videos…

**Preliminaries (part 2): The most important principle in Physics**

This video introduces one of the most important principles in Physics, that we’ll use later to solve some of the mysteries in Q.P. and Relativity theories.

**Preliminaries (part 3): Defining the building blocks**

This video introduces the notions of states and simultaneity, that we’ll use later to solve some of the mysteries in Q.P. and Relativity theories.

**Video #4: Defining Space**

This video re-defines the notion of space, that we’ll use later to solve some of the mysteries in Q.P. and Relativity theories…

**Video #5: Defining Time**

This video (re-)defines the notion of time, that we’ll use later to solve some of the mysteries in Q.P. and Relativity theories.

**Video #6: Answers to Q.P. Mysteries !**

This video finally answers the questions implied by the so-called “mysteries” in Q.P., using the elements defined and derived in the previous videos. It does not get into the maths details, which are developed in the next videos (videos 8 to 18), but gives a good idea of the steps to understand the answers in a logical, rational manner.

**Video #7: Answers to Relativity Mysteries !**

This video, the last one with (almost) no maths, explains why the “paradoxes” in both Special and General Relativity theories are not really mysteries, using the elements defined and derived in the previous videos… and logic. It does not get into the maths details, which are developed in the next videos (videos 8 to 18) and also in another playlist (see link below), but gives a good idea of the steps to understand the answers in a logical, rational manner.

**The Mathematical Videos (in English only): Maths Tools used to really solve “mysteries” in Quantum Physics and Relativity (explaining why we use some specific maths tools)**.

**Video #8: Why use complex numbers ?**

This video explains why complex numbers are so important and useful to describe how our Physical World works. Two other videos (#9 and #11) also talk about complex numbers usage, give some application examples, and will also help explain some of the quantum physics “mysteries”.

**Video #9: Why use Hilbert Spaces ?**

This video explains why and how Hilbert Spaces are used to describe the very important concept of “state” in Quantum Physics.

**Video #10: Why use Hermitian Operators ?**

This video explains why and how Hermitian Operators are used to describe and help understand quantum particle properties in Quantum Physics.

**Video #11: Examples of complex numbers usage**

This video gives some examples that show why and how Complex Numbers are used in Quantum Physics (and Relativity). Two other videos (#6 and #11) also explain why complex numbers are so important and useful to describe how our Physical World works, and will also help explain some of the quantum physics “mysteries”.

**Video #12: TUP, the most important principle in physics**

This video introduces one of the most important principles in Physics, that can be used to derive many laws of physics, in particular quantum physics and relativity, and thus resolve some of the “mysteries” in Q.P. and Relativity theories.

**Video #13: Explaining particle/wave duality and the stochastic character of Quantum Physics**

This video shows why and how Complex Numbers can be used to explain particle/wave duality and the stochastic character of Quantum Physics. Two other videos (#6 and #9) also explain why complex numbers are so important and useful to describe how our Physical World works, and also give some examples of how they are used in Quantum Physics (and Relativity).

**Video #14: Covariance and contravariance (mathematical interlude to introduce tensors…)**

This video introduces the concepts of covariance and contravariance (that will be useful to understand what tensors are in the next video), which are not always clearly defined/explained in the literature (or internet)…

**Video #15: What are tensors and why use tensors in Quantum Physics and Relativity ?**

This video introduces the concepts of tensors (which are not always clearly defined/explained in the litterature or internet), and explains why they are so useful to “simplify” the equations describing our Physical World, in particular in General Relativity theory.

**Video #16: What are metric tensors and why use them in Quantum Physics and Relativity ?**

This video introduces the concepts of metric tensor. It explains why the notion of metric tensor is key to understand how we measure space-time, and therefore are able to describe our Physical World laws.

**Video #17: Deriving General Relativity Equations from TUP (solving mysteries in Quantum Physics and Relativity)**

This video shows how to derive Einstein’s General Relativity Field Equations from the “Thrifty Universe Principle” (see video #10). While it is impossible to describe the details of this derivation, this video explains the major steps used to derive these very important (and complex…) equations from a very basic principle in physics.

**Video #18: Why a constant speed of light (postulate vs derivation) ?**

This video is the last one in the series, and shows how to derive the constance of speed of light by merely redefining the intuitive (but often incorrect) notion of time. This is a copy of video #3, with the addition of some mathematical derivations that show that this new definition is compatible with the existing theory of Special Relativity.

**Additional links:**

- Special Relativity Paradoxes (Twin’s paradox, etc.) are treated in details here:

https://www.youtube.com/watch?v=tcqUeBCrY7g&list=PLbzJ2a6XYN3lTXIKG7s2pjVNs6Eyl5Iv2 - The John Bell’s thought experiment that shows non-local causality quantum behaviors:

https://www.youtube.com/watch?v=kE9WPdJjlmA&list=PLbzJ2a6XYN3kHPkTt8MRyIrw2KnvXSAg1

- Video #17 relevant links:
- Link 1: https://en.wikipedia.org/wiki/Einstein%E2%80%93Hilbert_action
- Link 2: https://www.youtube.com/watch?v=A7IqjWCMlf8
- Link 3: http://web.mit.edu/edbert/GR/gr5.pdf (34)
- Link 4: http://web.mit.edu/edbert/GR/gr5.pdf (40)