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Efficient Sorting of Optical Vortices by Orbital-to-Spin Angular Momentum Coupling Effect
| Content Provider | Semantic Scholar |
|---|---|
| Copyright Year | 2014 |
| Abstract | The Hamiltonian is one of the most fundamental objects in quantum theory. It is used to describe the total energy of a physical system and governs the system’s time evolution, and thus it is postulated to be Hermitian for having real energy and for conserving probability. A possible extension of this postulate, called Parity-Time (PT) symmetry, would require the Hamiltonian to have spatialand time-reversal symmetry only, rather than the more restrictive Hermitian symmetry. This model was proposed in 1998 and stimulated much research to extend the fundamentals of quantum theory. Besides developing fundamental theory, PT symmetric theory also inspires a lot of research in classical optics. However, if such an extension is truly fundamental, some predictions of this theory would be extremely powerful, such as shortcuts in the evolution between two states or discrimination of two non-orthogonal states. Yi-Chan Lee from National Tsing-Hua University in Hsinchu City, Taiwan, and colleagues examine this new extension of quantum theory in the context of other physics principles, and show that the “local” form of PT symmetric theory would cause information transmission faster than light and thus is fundamentally flawed (or else special relativity is flawed, a highly unlikely proposition). In their paper, they follow two implicit assumptions in PT symmetry theory, describing how it locally exists and how to consider the description of quantum states in this theory. They put these assumptions into a composite system which is considered often in quantum information science. In this composite system, Alice and Bob share a pair of maximally entangled spins. They find that Alice could send information to Bob with a speed faster than light by choosing adequate local operations and measurements. To avoid this issue, one has to insist the same symmetry in local operations and measurements. Nevertheless, according to other research the authors point out these restrictions would make PT symmetry theory only an effective version of quantum theory rather than a fundamentally new theory. Based on their result they believe that PT symmetry theory either reduces to another version of standard quantum theory or is likely false as a fundamental theory. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://qolab.xmu.edu.cn/Research%20Highlights.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
