Direct Measurement Methods of Density Matrix of an Entangled Quantum State
arXiv:1911.06609 · doi:10.1088/2399-6528/ab9938
Abstract
In general, the state of a quantum system represented by density operator and its determination is a fundamental problem in quantum mechanics. A method of direct measurement of matrix element of density operator of a single two dimensional quantum system using weak measurement was theoretically proposed[Phys. Rev. Lett. 134, 070402(2012)] and experimentally demonstrated[Phys. Rev. Lett. 117, 120401(2016)] by Lundeen et al. Furthermore, recently the Guo-Guang Can et al.[Phys. Rev. Lett. 123, 150402(2019)] investigated the method of direct measurement of a nonlocal entangled quantum state. However, up to now the methods of directly measure the matrix element of density operator of an entangled quantum state have not been explicitly studied yet. As an extension of previous works, in this study we introduce two theoretical methods such as using postselected weak measurement and sequential measurements of triple products of complementary observables to direct measurement of matrix elements of density operator of two photon entangled quantum system, and discuss the similarity and the feasibility of those methods.
8pages
References in corpus (14)
- Direct measurement of the density matrix of a quantum system
- Compressive Direct Measurement of the Quantum Wave Function
- State tomography via weak measurements
- Modular values and weak values of quantum observables
- Experimental demonstration of direct path state characterization by strongly measuring weak values in a matter-wave interferometer
- Direct measurement of a nonlocal entangled quantum state
- Direct Reconstruction of the Quantum Density Matrix by Strong Measurements
- Strictly-complete measurements for bounded-rank quantum-state tomography
- Sequential measurement of conjugate variables as an alternative quantum state tomography
- Quantum optical reconstruction scheme using weak values
- Experimental simultaneous read out of the real and imaginary parts of the weak value
- Simultaneous weak measurement of non-commuting observables
- Weak measurement takes a simple form for cumulants
- Experimental nonlocal measurement of a product observable