Cleveland Comhrá: John Stewart Bell & The Bell Theorem
By Bob Carney
The earliest work on physics came to us twenty-five hundred years ago. Aristotle’s “Physica” tells us the world was made up of earth, air, fire and water and the heavens of a divine substance called ether. Other Greeks gave us a mathematical system for predicting the positions of the stars and the planets. Although many of these early writings proved to be incorrect, math and observation turned out to be essential to the progress of science.
Many of us are familiar with the “big” names in physics, Galileo, Newton, Tesla and Einstein. Einstein’s Theory of Relativity, which showed we could never travel faster than the speed of light, or his E=mc2 equation, which showed we could change objects into energy, paved the way for nuclear power.
In 1900, Max Planck, a German physicist, was able to show that the energy of electromagmetic waves is quantitized, so heat energy is emitted in chunks. This led to quantum physics, the science of the very small. The work in quantum physics gave us the transistor, which opened the way for our modern world, it’s application is in everything: medicine, transportation, communication and even our entertainment.
Since the 1920s, one of the main goals or thrust of physics has been to combine the theories of relativity and quantum physics into an explanation of the entire universe, a Grand Unified Theory. Of course it hasn’t happened, and could very well be impossible, or it could be possible but not by a human mind.
So physics is interesting because it tries to fit together this picture of the universe. But to understand one aspect, you need to understand another; but to understand that you need to understand the first, and so it goes!
One debate that lasted for quite sometime was over the physical phenomenom of quantum entanglement. Entanglement says that particles can instantly communicate with one another, even across cosmic distances. It is central to quantum computing, networking and the fabric of space and time.
Einstein dismissed quantum entanglement, calling it a “spooky action at a distance,” noting that random acts do not occur in mathematical equations. Danish physicist Neils Bohr received the Nobel Prize in Physics in 1922 for his contributions to understanding atomic structure and quantum theory. Bohr rebuked Einstein, and the two debated the topic for a number of years before it faded from the forefront of the physics community.
John Stewart Bell was born on the 28th of July, 1928, on Tate’s Avenue, Belfast. It was relatively peaceful in Belfast, where Stewart, as he was known at home, spent the first twenty-two years of his life.
John was an inquisitive child and an exceptional student in all his subjects, attending Ulsterville Junior School. He then entered Fane Street Elementary School at age eight. John’s father thought it natural for his children to attend school until the age of fourteen and then find a job.
His mother, Annie, had other ideas. She wished for her children to be educated so they would not have to work at physical tasks. From an early age, John was a regular visitor to the Donegal Road Public Library, reading and analysing as much as he could.
Secondary education in Britain was not free. In the 30s and 40s, the only way for children who came from families that were not well off to get an advanced education was to be awarded a scholarship. By the time John was eleven he had already passed the exams needed to continue his education with ease.
The cost of attending one of the prestigious grammar schools in Belfast was prohibitive, but enough money was found to get him into Belfast Technical High School. The curriculum there qualified him for entrance to a university along with the school’s vocational courses.
After high school, with his mother’s help, John landed a job as a technician in the physics department at Queen’s University Belfast. Senior members of the staff in the department soon realized his ability and potential and allowed him to borrow books and attend first year lectures. A year later, in 1945, he entered as a student, graduating in 1948 with first class honors in Experimental Physics. He spent one more year there, and earned a second degree, in Mathematical Physics, again with first class honors. He would have liked to work for his PhD, but economic reasons required him to get a job.
In 1949, he joined the UK Atomic Research Establishment at Harwell, and then moved to the Accelerator Design Group at Malvern. He met his future wife Mary there, and they married in 1954. He received his PhD in 1956 and four years later he and Mary moved to CERN, the Center for European Nuclear Research, in Geneva, where they remained for the rest of their carreers.
Quantum Theory and Bell’s Theorem
While particle physics and quantum field theory was what John was paid to work on, his passion was quantum theory. As an undergraduate, he was known to get into heated debates with his professors on the matter of quantum entanglement. That a disagreement on the subject by two prominent scientists as Einstein and Bohr should be regarded as unsolvable was not something John Stewart Bell could accept.
In 1964, Bell published a paper on the subject that later became known as Bell’s Theorem. He said that if measurements are performed independently on the two halves of a pair of particles, hidden variables, that Einstein termed, would correlate the outcome on the two halves. But the only way that hidden variables could explain the predictions of quantum physics is if they were “nonlocal”, somehow able to communicate instantly no matter how far they are seperated. Later he would write if a hidden variable is local, it will not agree with quantum mechanics, and if it agrees, it will not be local.
By 1972, tests were being run in experimental physics laboratories, trying to confirm Bell’s Theorem. At the time of his death in 1990, none of the experiments were conclusive; there was debate over the design or the set up of the tests and loopholes cast doubt on the results, although most agreed on the significance of Bell’s Theorem.
Finally, in 2015, a group of scientists travelled to the Canary Islands and using two of the world’s largest telescopes and light from distant quasars, conducted experiments that proved Bell’s Theorem and Einstein’s mistake, making John Stewart Bell one of the most acomplished physicsists of the last century.
*Bob Carney is a student of Irish history and language and teaches the Speak Irish Cleveland class held every Tuesday at PJ McIntyre’s. He is also active in the Irish Wolfhounds and Irish dogs orginizations in and around Cleveland. Wife Mary, hounds Morrighán and Rían and terrier Doolin keep the house jumping. He can be contacted at firstname.lastname@example.org