研究・研究者
研究会・セミナー
| 演 題 | 「Entanglement-assisted weak measurement and Heisenberg-limited precision」 |
|---|---|
| 日 時 | 2015年02月10日(火) 15:00 |
| 講演者 | Shengshi Pang （University of South California 博士研究員） |
| 場 所 | 南実験棟 408号室 |
| 概 要 | Large weak value amplification (WVA) has been of great interest for its potential in enhancing the sensitivity of measuring small physical parameters. However, a major shortcoming of WVA is the low utility of physical resources due to the postselection on the system. This has also led to the recent heated debate on the advantage of WVA in quantum metrology. In this research, we studied optimizing the choice of postselected state to maximize the postselection probability for a given weak value. It is found that entanglement between the initial systems can significantly reduce the resources discarded by postselection, and as a consequence increase the Fisher information of weak measurement. Based on this, we proposed an improved protocol of weak measurement assisted by entanglement. A remarkable result with this new protocol is that the loss of Fisher information by postselection can be reduced to as low as the order of the parameter, which is usually negligible in weak measurements, and the precision of the measurement can be enhanced to the well-known Heisenberg limit. To illustrate how to realize this protocol, some simple quantum circuits are provided for implementing it with qubits. |
| お問合せ先 | 鹿野 豊 |
