Events

Moses Misplon’s Comps Presentation
Monday, February 27th
8:30 am in Olin 141 

Closing Loopholes in Experimental Bell Tests 

Realism, the principle that physical objects and properties exist independent of our observations of them, has long been a foundation of the physical intuition of both physicists and humans in general. After Einstein’s development of the principle of relativity, which limits the propagation of information to the speed of light, it also seemed obvious that distant physical systems cannot cause instantaneous changes in each other, a concept known as locality. However, in 1964 John Bell proposed an experimental test that could disprove any and all local realistic theories. Although experimental Bell tests were quickly completed, they each suffered from a number of weaknesses in their experimental designs known as “loopholes” that prevented any definitive conclusion on local realism. Only in 2015 were the first “loophole-free” Bell tests conducted by building on years of technological advancements. I first will explain exactly how Bell developed a concrete experimental test of a pair of philosophical principles. Then I will discuss the unique technical challenges of experimental Bell tests that stymied experimenters for the past fifty years, and the three distinct routes the 2015 experiments took to overcome them. Finally, I will address the limitations of even these “loophole-free” tests, and the extent to which we can ever hope to address them.