To Find The Conditions Under Which Programmable Quantum States Can Be Unambiguously Discriminated

We are now living in the information age,where information technology and information science are needed in all fields.The rapid development of information science has brought great challenges to the classical information system,so quantum information science was born.In the field of quantum information,there are two major research hotspots.They are quantum computation and quantum communication.Many applications of quantum computation and quantum communication are inseparable from quantum state discrimination,so quantum state discrimination has been widely studied by researchers.The quantum state discrimination problem means that many quantum states form a set,and if you take a quantum state out of this set,how do you recognize this quantum state.Usually,the equatorial state,a special latitudinal state,is often used to study quantum communication both from theoretical and experimental perspectives.The main problem studied in this paper is the unambiguous discrimination of latitudinal states.First,the foundation and application of quantum information science is introduced.Then,the detailed description of optimal error-free discrimination scheme and the problem of optimal error-free discrimination of two unknown latitudinal states of uniform distribution are introduced.Finally,the problem of error-free discrimination of two unknown latitudinal states of arbitrary distribution is discussed.The detection operators and the successful probability are derived by using Neumark's theorem and the optical realization of the programmable quantum state discriminator.We find that the detection operators obtained in this paper are the same as the optimal detection operators obtained from the unambiguous discrimination of two unknown latitudinal states of uniform distribution.At the same time,we give a corresponding scheme of optical realization by using the single photon representation of quantum state and multi-track optical network.These results have important reference significance for the construction of the programmable quantum discriminator in laboratory.