Students can hide their ignorance and answer questions correctly in an exam without their lack of knowledge being detected by teachers -- but only in the quantum world.
University of Queensland researchers have successfully verified a counterintuitive idea from quantum theory -- that ignorance of the whole does not necessarily imply ignorance of the parts -- in the lab.
UQ physicist Dr Jacqui Romero from the ARC Centre of Excellence for Engineered Quantum Systems (EQUS) said the team's findings would be important when evaluating security in quantum encryption.
"What's also really nice is that we provide an accessible, real-world interpretation of a statement that comes from pure probability theory," Dr Romero said.
According to classical intuition, ignorance can be traced to a source -- if a student's knowledge of a book is incomplete, a teacher can design a test to probe which parts of the book are unknown to the student.
UQ PhD candidate and EQUS experimental physicist Michael Kewming said that this wasn't always the case in the quantum world.
"Our results confirm that the student's source of ignorance can be concealed from the teacher using quantum systems," Mr Kewming said.
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