In 1992, Hardy published a thought experiment that "makes nonsense of the famous interaction between matter and antimatter" — that when a particle meets its antiparticle, the pair "always annihilate one another" in a burst of energy.[5] Hardy proposed the possibility that in some cases when said interaction is not observed a particle and an antiparticle could interact with one another and survive. But since the interaction has to remain unseen, no one would notice this happening, which is why the result came to be known as Hardy's paradox.[6][7][5]
Five Reasonable Axioms
In 2001, Hardy published Quantum Theory From Five Reasonable Axioms, a paper that offered an axiomatic reconstruction of quantum theory. His proposal represented an "operational" approach made famous by Albert Einstein, but applied to quantum mechanics.[2]
In subsequent years, other authors built upon Hardy's work by proposing their own variants.[8][9]
^Hardy, Lucien (2001-01-03). "Quantum Theory From Five Reasonable Axioms". arXiv:quant-ph/0101012.
^Darrigol, Olivier (November 2015). "'Shut up and contemplate!': Lucien Hardy׳s reasonable axioms for quantum theory". Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics. 52, Part B: 328–342.