2 Quantum Tomographic Methods

D’Ariano, Giacomo Mauro; Paris, Matteo G. A.; Sacchi, Massimiliano F.

doi:10.1007/978-3-540-44481-7_2

Cited by 31 publications

(27 citation statements)

References 76 publications

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“…We analyze at varying the mean photon numbers of the interacting fields the different nonclassicality thresholds that appear. Remarkably, the corresponding transitions from classical to quantum domain may be observed experimentally by means of intensity measurements, thus avoiding full state reconstruction by homodyne or other phase-sensitive techniques [33,34].…”

Section: Introductionmentioning

confidence: 99%

Monitoring the quantum-classical transition in thermally seeded parametric down-conversion by intensity measurements

et al. 2009

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Abstract. We address the pair of conjugated field modes obtained from parametricdownconversion as a convenient system to analyze the quantum-classical transition in the continuous variable regime. We explicitly evaluate intensity correlations, negativity and entanglement for the system in a thermal state and show that a hierarchy of nonclassicality thresholds naturally emerges in terms of thermal and downconversion photon number. We show that the transition from quantum to classical regime may be tuned by controlling the intensities of the seeds and detected by intensity measurements. Besides, we show that the thresholds are not affected by losses, which only modify the amount of nonclassicality. The multimode case is also analyzed in some detail.

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Section: Introductionmentioning

confidence: 99%

Monitoring the quantum-classical transition in thermally seeded parametric down-conversion by intensity measurements

et al. 2009

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“…As shown in Ref [44], the only MUB structure for a two-qutrit system is (4,6), where 4 is the number of the separable bases and 6 is the number of the bipartite entangled bases. However in three-qutrit case, there are five sets of MUBs with different structures, namely {(0, 12, 16), (1,9,18), (2,6,20), (3,3,22), (4,0,24)} [21,44]. It is easy to see that the (0, 12, 16) set of MUBs has the minimum physical complexity.…”

Section: The Physical Complexity For Implementing the Mums In The mentioning

confidence: 99%

“…A main task for implementing quantum computation is to reconstruct the density matrix of an unknown state, which is called quantum state reconstruction or quantum state tomography [1,2]. The technique was first developed by Stokes to determine the polarization state of a light beam [3].…”

Section: Introductionmentioning

confidence: 99%

Optimal reconstruction of the states in qutrit systems

2010

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Based on mutually unbiased measurements, an optimal tomographic scheme for the multiqutrit states is presented explicitly. Because the reconstruction process of states based on mutually unbiased states is free of information waste, we refer to our scheme as the optimal scheme. By optimal we mean that the number of the required conditional operations reaches the minimum in this tomographic scheme for the states of qutrit systems. Special attention will be paid to how those different mutually unbiased measurements are realized; that is, how to decompose each transformation that connects each mutually unbiased basis with the standard computational basis. It is found that all those transformations can be decomposed into several basic implementable singleand two-qutrit unitary operations. For the three-qutrit system, there exist five different mutually unbiased-bases structures with different entanglement properties, so we introduce the concept of physical complexity to minimize the number of nonlocal operations needed over the five different structures. This scheme is helpful for experimental scientists to realize the most economical reconstruction of quantum states in qutrit systems.

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“…Tomograms for spin states have been developed both as projections on an arbitrary axis [54] as well as by using a discrete variable analog of symplectic tomography [55]. Tomograms of optical systems have been well studied in the past [6,11,24,56,57]. In Ref.…”

Section: Introductionmentioning

confidence: 99%

Tomograms for open quantum systems: In(finite) dimensional optical and spin systems

2016

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Tomograms are obtained as probability distributions and are used to reconstruct a quantum state from experimentally measured values. We study the evolution of tomograms for different quantum systems, both finite and infinite dimensional. In realistic experimental conditions, quantum states are exposed to the ambient environment and hence subject to effects like decoherence and dissipation, which are dealt with here, consistently, using the formalism of open quantum systems. This is extremely relevant from the perspective of experimental implementation and issues related to state reconstruction in quantum computation and communication. These considerations are also expected to affect the quasiprobability distribution obtained from experimentally generated tomograms and nonclassicality observed from them.

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2 Quantum Tomographic Methods

Cited by 31 publications

References 76 publications

Monitoring the quantum-classical transition in thermally seeded parametric down-conversion by intensity measurements

Monitoring the quantum-classical transition in thermally seeded parametric down-conversion by intensity measurements

Optimal reconstruction of the states in qutrit systems

Tomograms for open quantum systems: In(finite) dimensional optical and spin systems

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