Measurement strategy for spatially encoded photonic qubits

Solís-Prosser, M. A.; Neves, Leonardo

doi:10.1103/physreva.82.055801

Cited by 10 publications

(28 citation statements)

References 15 publications

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“…Most of those applications has benefited from the recent developments on the control of spatial qudits based on the technology of electrically addressed spatial light modulators (SLMs). SLMs have dramatically simplified and broadened the range of operations that can be implemented in real time on spatial qudits for state preparation, transformation and measurement [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Optimized generation of spatial qudits by using a pure phase spatial light modulator

Varga¹,

Rebón²,

Solís-Prosser³

et al. 2014

J. Phys. B: At. Mol. Opt. Phys.

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Abstract:We present a method for preparing arbitrary pure states of spatial qudits, namely, D-dimensional (D ≥ 2) quantum systems carrying information in the transverse momentum and position of single photons. For this purpose, a set of D slits with complex transmission are displayed on a spatial light modulator (SLM). In a recent work we have shown a method that requires a single phase-only SLM to control independently the complex coefficients which define the quantum state of dimension D. The amplitude information was codified by introducing phase gratings inside each slit and the phase value of the complex transmission was added to the phase gratings. After a spatial filtering process we obtained in the image plane the desired qudit state. Although this method has proven to be a good alternative to compact the previously reported architectures, it presents some features that could be improved. In this paper we present an alternative scheme to codify the required phase values that minimizes the effects of temporal phase fluctuations associated to the SLM where the codification is carried on. In this scheme the amplitudes are set by appropriate phase gratings addressed at the SLM while the relative phases are obtained by a lateral displacement of these phase gratings. We show that this method improves the quality of the prepared state and provides very high fidelities of preparation for any state. An additional advantage of this scheme is that a complete 2π modulation is obtained by shifting the grating by one period, and hence the encoding is not limited by the phase modulation range achieved by the SLM. Numerical simulations, that take into account the phase fluctuations, show high fidelities for thousands of qubit states covering the whole Bloch sphere surface. Similar analysis are performed for qudits with D = 3 and D = 7.

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Section: Introductionmentioning

confidence: 99%

Optimized generation of spatial qudits by using a pure phase spatial light modulator

Varga¹,

Rebón²,

Solís-Prosser³

et al. 2014

J. Phys. B: At. Mol. Opt. Phys.

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show abstract

“…This strategy is based on our recent work [30] and, as we will see, at the expense of increasing the classical communication cost as well as the experimental resources, it improves the figures of merit of the RSP protocol when compared with spatial postselection alone. The strategy can be divided into two steps: first, the implementation of a two-outcome POVM with the polarization as the ancillary system and second, the spatial postselection at the focal plane of the lens by a two-pixel detector in each output of the POVM.…”

Section: Rsp Of Spatial Qubits Via Generalized Measurementsmentioning

confidence: 99%

“…Previously, we saw how the twopixel detectors move within each arm [see Eq. (30)]. Now we impose an extra condition between the positions of these arms (p = H,V ) given by…”

Section: Conditions For Remotely Preparing the Target Statementioning

confidence: 99%

Remote state preparation of spatial qubits

Solís-Prosser

Neves

2011

Phys. Rev. A

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We study the quantum communication protocol of remote state preparation (RSP) for pure states of qubits encoded in single photons transmitted through a double slit, the so-called spatial qubits. Two measurement strategies that one can adopt to remotely prepare the states are discussed. The first strategy is the well-known spatial postselection, where a single-pixel detector measures the transverse position of the photon between the focal and the image plane of a lens. The second strategy, proposed by ourselves, is a generalized measurement divided into two steps: the implementation of a two-outcome positive operator-valued measurement (POVM) followed by the spatial postselection at the focal plane of the lens by a two-pixel detector in each output of the POVM. In both cases we analyze the effects of the finite spatial resolution of the detectors over three figures of merit of the protocol, namely, the probability of preparation, the fidelity and purity of the remotely prepared states. It is shown that our strategy improves these figures compared with spatial postselection, at the expense of increasing the classical communication cost as well as the required experimental resources. In addition, we present a modified version of our strategy for RSP of spatial qudits which is able to prepare arbitrary pure states, unlike spatial postselection alone. We expect that our study may also be extended for RSP of the angular spectrum of a single-photon field as an alternative for quantum teleportation which requires very inefficient nonlinear interactions.Comment: 17 pages, 8 figures. Published versio

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“…The point-like detector is constructed using a pinhole in front of a conventional bulk APD, which is then positioned at the center of the interference pattern. In this configuration, the probability of single-photon detection at the APD is proportional to [20][21][22][23]. During the implementation of the KS tests, the modulations performed by SLM1 and SLM2 remain fixed producing the quantum state to be used in the test.…”

Section: Methodsmentioning

confidence: 99%

Experimental implementation of an eight-dimensional Kochen-Specker set and observation of its connection with the Greenberger-Horne-Zeilinger theorem

et al. 2014

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For eight-dimensional quantum systems there is a Kochen-Specker (KS) set of 40 quantum yes-no tests that is related to the Greenberger-Horne-Zeilinger (GHZ) proof of Bell's theorem. Here we experimentally implement this KS set using an eight-dimensional Hilbert space spanned by the transverse momentum of single photons. We show that the experimental results of these tests violate a state-independent noncontextuality inequality. In addition, we show that, if the system is prepared in states that are formally equivalent to a three-qubit GHZ and W states, then the results of a subset of 16 tests violate a noncontextuality inequality that is formally equivalent to the three-party Mermin's Bell inequality, but for single eight-dimensional quantum systems. These experimental results highlight the connection between quantum contextuality and nonlocality for eight-dimensional quantum systems.

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Measurement strategy for spatially encoded photonic qubits

Cited by 10 publications

References 15 publications

Optimized generation of spatial qudits by using a pure phase spatial light modulator

Optimized generation of spatial qudits by using a pure phase spatial light modulator

Remote state preparation of spatial qubits

Experimental implementation of an eight-dimensional Kochen-Specker set and observation of its connection with the Greenberger-Horne-Zeilinger theorem

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