Quantum mechanics - NOT amateur radio

Many years ago (late 1960s) I did a course on quantum mechanics at university. If I remember correctly, everything can be thought of as a wave function that exists in all space and all time. What we think of as the "here and now" is the most probable.  Tunnel diodes only work because of quantum mechanical tunneling.

According to quantum entanglement, particles at opposite ends of the universe can have some sort of affinity, which would not conform with relativity.

What is certain is how little we know.

Quantum Mechanics - NOT amateur radio

 Quantum mechanics is hard and in many ways counter-intuitive. This YouTube video may help.

Quantum mechanics - NOT amateur radio

My 6 week course on an aspect of quantum mechanics as part of my University of The Third Age in Cambridge (U3AC) has ended. It was very hard!  It was given by a very well qualified Cambridge University physicist. He is a good presenter.

The takeaway comment at the end of the course was "spooky actions at a distance", Einstein's comment, really do occur. This means that at far ends of the universe things can influence each other instantly. This action occurs instantly and does not depend on the speed of light. This has been proved conclusively by experiments.  Einstiein did not want to believe this and did all sorts of things to try and disprove this. He failed.

This suggests what we think of as reality is not. This is totally counter intuitive.  All we can say really is there is very much we do not know.

Quantum mechanics - NOT amateur radio

One advantage of being near Cambridge is we have a vast choice of courses for our University of the Third Age. Often we can tap into the knowledge of some very clever people.

I go into Cambridge to learn about Medieval History on Fridays and attend a course on Quantum Mechanics at home on Zoom on Tuesday mornings. The course on quantum mechanics is given by a Cambridge Ph.D man. He is a very good communicator, but it is hard.

The important things are the "take away" remarks. Repeated experiments seem to prove that quantum mechanics is right and our "conventional" view of reality is flawed. Indeed, our whole beliefs about space and time may be wrong. 

This is as much about philosophy as physics.

Quantum time machine?

Researchers at MIT may have come up with a way of travelling through time (and space) using quantum closed timeline curves or CTCs. It has always fascinated me that in quantum mechanics one can describe things as wave functions that have existed in all space and all time, past present and future. It takes a leap of imagination to consider the possibilities. For an explanation see http://www.telegraph.co.uk/science/7904712/Quantum-time-machine-allows-paradox-free-time-travel.html

This is the abstract of the original MIT paper:

"This paper discusses the quantum mechanics of closed timelike curves (CTC) and of other potential methods for time travel. We analyze a specific proposal for such quantum time travel, the quantum description of CTCs based on post-selected teleportation (P-CTCs). We compare the theory of P-CTCs to previously proposed quantum theories of time travel: the theory is physically inequivalent to Deutsch's theory of CTCs, but it is consistent with path-integral approaches (which are the best suited for analyzing quantum field theory in curved spacetime). We derive the dynamical equations that a chronology-respecting system interacting with a CTC will experience. We discuss the possibility of time travel in the absence of general relativistic closed timelike curves, and investigate the implications of P-CTCs for enhancing the power of computation."

Simple ??? See http://arxiv.org/abs/1007.2615