Cross posted from FQXi’s blog: https://fqxi.org/community/forum/topic/3253
From the start, this was an ambitious project. Our aim was to introduce quite challenging philosophical concepts deeply embedded in quantum mechanics. Our target audience was broad: we hoped that anyone from school science students to academic quantum physicists would both learn something, and be entertained, by the book. And finally, the book is short – only six double page spreads – and contains minimal text, with the intention that the illustrations play a central part in conveying the concepts we introduce. So, have we succeeded? You can find out by reading the book online here.
The seed of this project began when I undertook a short Postdoc, as part of FQXi’s physics of the observer program, at the University of Nottingham, with supervisors Prof Gerardo Adesso, Dr Tommaso Tufarelli, and Dr Marco Piani. The general question I was to dive into was: Why does our everyday world look the way it does, despite being made of bizarre quantum mechanical particles? Quantum entities, such as electrons, atoms, and photons, perpetually exist in bizarre states: they can be in two places at the same time, be travelling in multiple directions simultaneously, and can even teleport. But if everyday objects – such as chairs, tables and cats – are made of such things, then why do they look so normal?
The more specific question we hoped to answer related to the concept of objectivity. If two people look at the same object then they invariably agree on the details, such as the size, shape, and orientation, of the object. These properties are said to be objective. But, due to the bizarre quantum world discussed above, it is not clear at first sight why objects that are made of quantum mechanical particles should look objective. To cut a long story short, our work during this project, together with previous quantum physicists’ results, demonstrated that the mathematical structure of quantum mechanics itself implies that everyday objects should indeed have objective properties. As part of this project we collaborated with the same artist, Joseph Namara Hollis, to produce an illustration related to our work, which we were honoured to be selected for the front cover of Physical Review Letters.
But despite the success of this work, I wasn’t quite satisfied with the philosophical backdrop to our findings. Our results were mainly concerned with why we observe the world to be objective. But using the quantum mechanical formalism we can go beyond our mere observations, and ask questions about the whole of reality – the observed and the unobserved – in which we live. And when I plunged into such questions, I emerged with a strong view that the equations of quantum mechanics are really telling us that our universe is only one in an unimaginably large number of parallel universes! This is certainly not the only conclusion that can be drawn from the equations of quantum mechanics, but for reasons that I explain here I personally find this the most convincing and compelling.
This brings us to the main motivation of creating the FQXi-sponsored illustrated book that this blog pertains to. When we use both philosophy and physics to dive into the question of what quantum physics really tells us about reality, it turns out that there are many possible answers (of which quantum parallel-universes is just one). Other answers include that quantum mechanics must be incorrect or incomplete, and a revised theory is necessary in order to make sense of reality; or that quantum mechanics is really telling us about our knowledge of the world, rather than directly relating to the objects in our surroundings themselves. But when scouring through the literature to try to understand this, I found that the introductions and explanations to the different theories were dense and complicated, and it seemed impossibly hard to form a simple, overarching picture of what quantum mechanics tells us about reality.
This, then, is the purpose of the book: to create a (relatively) straightforward overview of the various theories that quantum physicists use to explain reality; and to introduce the philosophical conundrum at the heart of quantum mechanics that requires such an array of theories to be introduced. And to do all this is an entertaining and intuitive way by using the beautiful and fantastical illustrations of Joseph Namara Hollis.
We invite you to take a look at the book, which is freely available, and let us know what you think!