Is it possible that a measurement of a spin component of a spin-1/2 particle yields the value 100?In 1988 Aharonov,Albert and Vaidman argued that upon pre-and postselection of particular spin states,weakening the coup...Is it possible that a measurement of a spin component of a spin-1/2 particle yields the value 100?In 1988 Aharonov,Albert and Vaidman argued that upon pre-and postselection of particular spin states,weakening the coupling of a standard measurement procedure ensures this paradoxical result1.This theoretical prediction,called weak value,was realised in numerous experiments2-9,but its meaning remains very controversialsince its"anomalous"nature,i.e.z the possibility to exceed the eigenvalue spectrum,as well as its"quantumness"are debated20-22.We address these questions by presenting the first experiment measuring anomalous weak values with just a single click,without the need for statistical averaging.The measurement uncertainty is significantly smaller than the gap between the measured weak value and the nearest eigenvalue.Beyond clarifying the meaning of weak values,demonstrating their non-statistical,single-particle nature,this result represents a breakthrough in understanding the foundations of quantum measurement,showing unprecedented measurement capability for further applications of weak values to quantum photonics.展开更多
基金We acknowledge the European Union's Horizon 2020 and the EMPIR Participating States in the context of the projects 17FUN01"BeCOMe"and 17FUN06"SIQUST",the European Union's Horizon 2020 FET-OPEN project grant no.828946"PATHOS"the National Science Foundation--U.S.-lsrael Binational Science Foundation Grant No.735/18.+1 种基金EC was supported by Grant No.FQXi-RFPthe Quantum Science and Technology Program of the Israeli Council of Higher Educatio n,and the Pazy Foundation.
文摘Is it possible that a measurement of a spin component of a spin-1/2 particle yields the value 100?In 1988 Aharonov,Albert and Vaidman argued that upon pre-and postselection of particular spin states,weakening the coupling of a standard measurement procedure ensures this paradoxical result1.This theoretical prediction,called weak value,was realised in numerous experiments2-9,but its meaning remains very controversialsince its"anomalous"nature,i.e.z the possibility to exceed the eigenvalue spectrum,as well as its"quantumness"are debated20-22.We address these questions by presenting the first experiment measuring anomalous weak values with just a single click,without the need for statistical averaging.The measurement uncertainty is significantly smaller than the gap between the measured weak value and the nearest eigenvalue.Beyond clarifying the meaning of weak values,demonstrating their non-statistical,single-particle nature,this result represents a breakthrough in understanding the foundations of quantum measurement,showing unprecedented measurement capability for further applications of weak values to quantum photonics.
