Quantum field theory has also enabled us to bring the different versions of quantum physics under one roof and almost anything we want to study now, from food chemistry to flame-throwers, can be understood with the same starting assumption: the Universe is a collection of overlapping fields and what we think of as matter is just three-dimensional bumps forming in these fields. Not to mention predicting the so-called ‘fine structure constant’ (a measure of how well electrons interact with light) to the highest number of decimal places ever recorded. The existence of antimatter and neutrinos for another. The existence of the Higgs boson for one. You might find the idea that you aren’t really made of anything unsettling, but quantum field theory has made a string of knockout predictions which make it hard to dismiss. The particles we use in normal physics to describe the world are not really lumps of stuff moving through space, they are miniature tornadoes formed from the all-pervading fields which flood our Universe. We call these little clots of energy appearing in the field ‘quanta’ or, if you prefer, particles. Just like the water in our ocean analogy or the air in our tornado analogy, these fields are typically dormant, but if they get agitated, pockets of turbulence can bubble into existence and move around as if they were separate objects. It is filled with what physicists call ‘fields’ - fluid-like substances which extend in all directions. In quantum field theory, empty space is not genuinely empty. One of the greatest achievements of human civilisation? This, according to quantum field theory, is how we need to understand particles. It looks like a distinct entity moving independently of the placid water around it, but we know that the wave and its surroundings are really made from the same stuff. The same can be said for a wave undulating across the surface of the ocean.

It is just a fluctuation, whipped together from the surrounding air. Although we think of it as a self-contained object we know it is not truly a ‘thing’ in its own right. Picture a tornado moving through the air. Quantum field theory solves the conundrum by making a radical change to the picture: scrap the idea of particles altogether because they don’t really exist. It’s a useful way of picturing the Universe but it doesn’t explain why different types of particle follow different sets of laws. When we do normal physics we traditionally visualise particles as little balls zipping around in empty space. We therefore need to prove that we genuinely know what the central idea states, and this is where things get strange (aka worth studying). Presumably of course, the aliens listening to our plea will have already discovered quantum field theory for themselves. We really have discovered a unifying principle which seems to account for the whole of quantum physics and all that remains is to extrapolate the principle to different scenarios. It’s a lofty ambition, but what we need to point out to the aliens judging us is that we have actually been successful in doing it. Quantum field theory is an attempt to unite these different sets of laws and formulate a single framework that accounts for everything in one go, rather than having multiple flavours of the same theory. The quantum rules governing nuclear explosions are different to the quantum rules governing mutations of DNA so there isn’t just one version of quantum physics, there are several. That’s the goal of quantum physics to learn all the fundamental laws of particles and use them to understand everything.īut things get very complicated very quickly because each type of particle has its own set of laws.

The more we know about how particles behave, the more phenomena we can explain.

Here goes.Īny object can be described in terms of its constituent particles and any event can be described in terms of how those particles interact. My presentation may not feature Jason Statham roundhouse kicking a shark in the eyeball, but I am going to try and justify the continued existence of the human race. Therefore, your honour, I request that you give me five minutes of your intergalactic attention.

The idea of summarising it in 1,500 words or less for this article sounded daunting at first (it took a whole chapter to cover it in my recent book) but then again if I really did have to present it to a jury of aliens I wouldn’t have a choice. It looks like an unholy crossbreed between quantum physics in a bad mood and every button you never push on a calculator. Quantum field theory doesn’t get much coverage in popular science and if you open any textbook on the subject you’ll see why. Quantum theory: the weird world of teleportation, tardigrades and entanglement.Dead and alive: why it's time to rethink quantum physics.

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