Einstein has become a by-word for being clever and being right. Is that not what ‘being an Einstein’ means?

Einstein, however, was wrong on Quantum Mechanics. Quantum Mechanics or Quantum Theory (the basis for Quantum Computing) is the branch of mechanics that deals with the mathematical description of the motion and interaction of subatomic particles, aiming to quantify (measure and calculate) energy, particle duality, the uncertainty principle, and the correspondence principle. Quantum Mechanics – in short - studies nature’s smallest and invisible particles and tries to ‘capture’ the irregular behaviour of these particles by mathematically determining them. Why? Because energy and light (entangled waves of particles) affect everything we do, even if we can’t see them.

**Quantum Mechanics and how it came about**

Quantum Mechanics totally defies human logic as the minuscule, invisible, particles it studies move backward and forward at will and can exist in two places at the same time (SEE OUR ARICLE ON QUANTUM COMPUTING). This is what makes it all so incomprehensible. Quantum Mechanics and Quantum Theory were developed about a 100 years ago by the Danish physicist **Niels Bohr** (the 1922 Winner of the Nobel Prize for Physics). His thesis was centred on the idea of superposition and complementarity of particles and the fact that these invisible particles did not have physical properties, but only probabilities. Quantum Mechanics therefore accepted a degree of ‘un-measurability’ of the particles and this is exactly what riled Einstein.

**Einstein’s view on Quantum Mechanics**

Einstein believed everything in science had to be real; had to have a physical, quantifiable reality and he famously stated that: “*What we call science has the sole purpose of**determining what is”,* aka not what can be, could be or would be. Einstein proclaimed a scientific realism, the fundamental reality of observable and measurable science as opposed to the scientific probability of an invisible reality as Bohr suggested. Although Einstein and Bohr were friends and had great respect for one another, Einstein was determined to prove that Quantum Mechanics could not be a complete theory of the physical world and hence had to be flawed.

To prove it, Einstein, with colleagues Podolsky and Rosen (EPR for short), published a paper in 1935 titled ‘**Can Quantum-Mechanical Description of Physical Reality be Considered Complete?’.**

**Einstein’s counter ‘attack’: the EPR Paradox **

Einstein, Podolsky and Rosen wanted to measure the probability of particles, i.e. making them real, by setting up two systems, where the first system allowed superposition, interaction and entanglement of particles and the second system would subsequently separate them, so that no further interaction between particles would occur. Certainly, the behaviour and mathematical property of particles in ‘action’ in system one could later be determined by seeing how they would individually behave when separated in system two? This was the main research objective of the EPR Paradox.

EPR argued that Quantum Mechanics was incomplete because of three main issues that arose when trying to quantify the properties of the particles studied in these two systems and hence proved Bohr was wrong. The EPR Paradox demonstrated that the science of Quantum Mechanics was flawed, because: (1) there was an incompliance with the **Criterion of Reality** (scientific realism); (2) it violated the **Heisenberg Uncertainty Principle** (basically saying that the velocity and position of an object can NOT be measured at the same time exactly), and (3) it proclaimed the **impossibility of distant****particles having simultaneous realities** (this is still today what very few people can wrap their heads around and why Quantum Computing is so complex).

It is worth noting that Einstein was not attempting to disprove Quantum Mechanics altogether. He was merely troubled by the probabilistic nature of the theory and its subsequent philosophical implications for wider science. He thought Quantum Mechanics was inconsistent and not aligned to the (then) current law of physics.

To account for the discrepancy between Bohr’s and his views of Quantum Mechanics, Einstein finally accepted an existence of hidden variables: the yet unknown local properties of the theory and left it at that, without ever fully accepting Bohr’s theory. The two men never agreed and for 30 years their academic disagreement remained unresolved.

**Who and what resolved the dispute?**

The issue of probability in Quantum Mechanics remained unresolved until the Irish physicist **John Bell decided to settle the dispute**. In 1964 he had a go at Einstein’s idea of the ‘hidden variables’ and introduced a mechanism to test them.

He developed a series of inequalities, now known as **Bell Inequalities**, which represented how measurements of the entanglement of two particles would distribute if they were not entangled, i.e separated. He managed to calculate what the EPR Paradox had failed to do. What had previously been a philosophical debate suddenly had testable consequences. Bell was able to prove quantum entanglement and hence Quantum Mechanics’ completeness. He added measurability to Bohr’s theory.

**Critical thinking and Einstein’s error**

Despite Einstein's genius, his challenge to Quantum Mechanics was quickly overturned. Today, quantum entanglement forms the foundation of revolutionary technologies, such as quantum cryptography and Quantum Computing, and undoubtedly will help establish many new ones. If Einstein would not have disagreed, would Quantum Mechanics and Quantum Computing already be much further ahead than they are today? Was it the unshakable belief in Einstein’s genius that made the scientific world accept his view – rather than focussing on Bohr ‘s novel theories? Was it a case of confusing the messenger and the message?

Ask your inner Einstein.

**Recommended links:**

https://www.talksforteens.com/tech/you-dont-have-to-understand-quantum-computing

https://plato.stanford.edu/entries/qt-epr/

https://www.livescience.com/33816-quantum-mechanics-explanation.html

https://en.wikipedia.org/wiki/Niels_Bohr

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