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Multi-mode density matrices of light via amplitude and phase control
| Content Provider | Semantic Scholar |
|---|---|
| Author | Opatrný, Tomás Friedrich-Schiller, D.-G. Welsch |
| Copyright Year | 1996 |
| Abstract | A new method is described for determining the quantum state of correlated multimode radiation by interfering the modes and measuring the statistics of the superimposed fields in four-port balanced homodyne detection. The full information on the N-mode quantum state is obtained by controlling both the relative amplitudes and the phases of the modes, which simplifies the reconstruction of density matrices to only N + 1 Fourier transforms. In particular, this method yields time-correlated multimode density matrices of optical pulses by superimposing the signal by a sequence of short local-oscillator pulses. Recently, increasing interest has been devoted to the problem of reconstruction of the quantum state of optical fields from measurable data. The feasibility of reconstruction of single-mode density matrices was first demonstrated by Smithey et al. [1] using optical homodyne tomography. In the experiments they determined both the Wigner function and the density matrix in a field-strength basis. Later, the problem of direct reconstruction of the density matrix in a field-strength basis and the photon-number basis has been studied in Refs. [2] and [3], respectively. All these methods are based on the fact that in balanced homodyne four-port detection the field-strength distributions of a signal mode can be measured and knowledge of the field-strength distributions for all phases within a π-interval is equivalent to knowledge of the quantum state of the mode [4]. Whereas for determining the Wigner function a threefold integral must be calculated, the direct reconstruction of the density matrix elements can be accomplished with two integrals. The method has first been extended to two-mode quantum states [5] and later on the general situation for reconstructing N-mode quantum states from N-fold joint difference-count distributions has been investigated |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://arxiv.org/pdf/quant-ph/9604020v1.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Density matrix Experiment Fast Fourier transform Fock state Local oscillator Oscillator Device Component Photons Quantum state Tomography Wigner quasiprobability distribution newton |
| Content Type | Text |
| Resource Type | Article |
