In their experiments, the two researchers were able to prove that Bell’s inequality is indeed violated. In the early 1970s, John Francis Clauser, who was awarded the Nobel Prize in Physics last year, and Stuart Freedman carried out the first practical Bell test. Credit: ETH Zurich / Daniel Winkler The last doubts dispelled

Several layers of copper shielding protect the conductor from thermal radiation. An aluminum waveguide (center), cooled to almost absolute zero, connects the two quantum circuits. Bell wanted to settle a question that the greats of physics had already argued about in the 1930s: Are the predictions of quantum mechanics, which run completely counter to everyday intuition, correct, or do the conventional concepts of causality also apply in the atomic microcosm, as Albert Einstein believed?Ī view inside a section of the 30-meter-long quantum connection. An old disputeĪ Bell test is based on an experimental setup that was initially devised as a thought experiment by British physicist John Bell in the 1960s. What’s special about this experiment is that the researchers were able for the first time to perform it using superconducting circuits, which are considered to be promising candidates for building powerful quantum computers. By showing that quantum mechanical objects that are far apart can be much more strongly correlated with each other than is possible in conventional systems, the researchers have provided further confirmation for quantum mechanics. Credit: ETH Zurich / Daniel WinklerĪ group of researchers led by Andreas Wallraff, Professor of Solid State Physics at ETH Zurich, has performed a loophole-free Bell test to disprove the concept of “local causality” formulated by Albert Einstein in response to quantum mechanics.

The vacuum tube (center) contains a microwave waveguide that is cooled to around –273☌ and connects the two quantum circuits. Partial section of the 30-meter-long quantum connection between two superconducting circuits.

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