Quantum physics can seem intimidating, weird and counter-intuitive, even for the physicists who deal with it every day. But it’s not beyond your understanding.
In order to get a grasp of quantum physics – there are six ideas that you need to understand.
- Everything is made of Waves and also Particles
Everything in the universe has both particle and wave nature. This seems crazy, but it is an experimental fact.
However, to be precise the objects described by quantum physics are neither particles nor waves, but a third category that shares some properties of waves (they have characteristics of frequency and wavelength) and some properties of particles (that are countable and can be localized to some degree). This make the physics community wonder if it’s really appropriate to talk about light as a particle in beginners physics courses. This exists, not because there’s any controversy about whether light has some particle nature, but because calling photons “particles” rather than “excitations of a quantum field” might lead to misconceptions.
Wave, particle or field – why is this important? The Higgs boson was discovered at the Large Hadron Collider as a particle, but you will also hear physicists talk about the “Higgs field”. The “Higgs field” is a delocalized thing filling all of space. This happens because in some circumstances, such as in collider experiments, it’s more convenient to discuss excitations of the Higgs field in a way that emphasizes the particle-like characteristics, while in other circumstances, like general discussion of why certain particles have mass, it’s more convenient to discuss the physics in terms of interactions within a universe-filling quantum field. This different terms exist to describe different phenomena of the same quantum object.
- Quantum Physics Is Discrete
The word “quantum” comes from the Latin ‘quanta’ meaning “how much” This reflects the fact that quantum models always involve something having discrete characteristics. The energy contained in a quantum field comes in the form of some fundamental energy. For light, this field is associated with the frequency and wavelength of the light– high-frequency, short-wavelength light has a large characteristic energy, while low-frequency, long-wavelength light has a small characteristic energy. So even at quantum level – observations are discrete and measurable.
- Quantum Physics Is Probabilistic
One of the most surprising and controversial aspects of quantum physics is that it’s impossible to predict with certainty the outcome of a single experiment on a quantum system. When physicists predict the outcome of some experiment, the prediction always takes the form of a probability for finding each of a number of possible outcomes. Comparisons between theory and experiment always involve inferring probability distributions from many repeated experiments.
There is also an aspect of quantum theory that describes particles as being in multiple states at the same time. Hence all that can be predicted is a probability. Prior to a measurement that determines a particular outcome, the system being measured is in an indeterminate state that can map onto a multiple possibilities with different probabilities.
Whether you consider this as the quantum system really being in all of the states at once, or just being in one unknown state depends largely on your feelings and method of thinking.
- Quantum Physics Is Non-Local
The last great contribution Einstein made to physics was not widely recognized as such, mostly because he was wrong. In a 1935 paper with his younger colleagues Einstein provided a clear mathematical statement of something that had been bothering him for some time, an idea that we now call “entanglement.”
This paper argued that quantum physics allowed the existence of systems where measurements made at distant locations could be correlated in ways that suggested the outcome of one was determined by the other. They argued that this meant the measurement outcomes must be determined in advance, by some common factor, because the alternative would require transmitting the result of one measurement to the location of the other at speeds faster than the speed of light. Thus, Einsteins team They proposed a “local hidden variable” theory, where the results of a particular measurement do not depend on anything farther away from the measurement location than a signal could travel at the speed of light (“local”). But the correlation is determined by some “hidden variable” common to both systems in an entangled pair.
This idea was tolerated by the physics community for about 30 years, as there seemed to be no way to test it. However, in the mid-1960’s the Irish physicist John Bell showed that you can find circumstances in which quantum mechanics predicts correlations between distant measurements that are stronger than the “hidden variable”theory. This was tested experimentally in the mid-1970’s by John Clauser and Alain Aspect in the early 1980’s, These experiments are considered to have definitively shown that these entangled systems cannot possibly be explained by any local hidden variable theory.
The most common way to explain the effects that occur at a distant is to say that quantum mechanics is non-local. The results of measurements made at a particular location can depend on the properties of distant objects in a way that can’t be explained using signals moving at the speed of light. These particles are entangled in ways that science does not yet understand.
- Quantum Physics Is (Mostly) Very Small
Quantum physics has a reputation of being weird because its predictions are dramatically unlike our everyday human experience. This happens because the effects involved get smaller as objects get larger.
For the most part, quantum phenomena are confined to the scale of atoms and fundamental particles. There is an active effort though, to push the size of systems showing quantum effects up to larger sizes.
- Quantum Physics Is Not Magic
As weird as it may seem, quantum physics is most not magic. Magic often refers to things that we cannot explain. Once explained it ceases to be magic. While quantum physics predictions are strange by the standards of everyday physics, they are based on well-understood mathematical rules and principles.
However, much is not understood about the quantum universe. So may be there is a little magic left….
Dr Nitasha Buldeo is an Integrated Medical Practitioner, Entrepreneur, Scientist and Yogi. She created I-Yoga & Organic Apoteke and is Director of the Centre for Exceptional Human Performance. She researches human potential and delivers programs that encourage you to live exceptionally. Nitasha believes that every one of us is striving to be the best we can. Her passion is bringing you experiences that inspire you. Her intention is for you to unlock your genius.