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We implement a single-photon subtractor that can be tuned to subtract a single photon exclusively from one mode or coherently from multiple modes. We experimentally characterize the device by employing coherent-state quantum process tomography.
Single-photon subtracting operation plays important roles in photonic quantum information processing. For example, it enables distillation of entanglement, noiseless amplification of a quantum state, and enhancement of measurement precision. In particular, the non-Gaussian characteristic of the operation is essential for genuine speed-up and universality of continuous-variable quantum computing. Until...
We present a method to characterize single-photon subtraction process in multiple time-frequency modes. To obtain complete information of the process, we use coherent-state quantum process tomography, and express the results by a quantum process matrix.
We report another regime for generation of time-bin entangled photon pairs and demonstrate the scheme experimentally. In our scheme, the photon pairs are pumped by a cw multi-mode laser having coherence revival property.
We report the generation of a photon-number entangled state in which detection of ancillary photons heralds the generation of the entangled state as well as its phase. Our scheme can operate with separable input states.
We observed nonmonotonic dependence of a many-particle detection probability on the particles' mutual distinguishability. Such nonmonotonicity is a generic feature of the quantum-to-classical transition in multiparticle systems.
We report the first experimental implementation of an approximate partial transpose operation for photonic two-qubit systems. Direct detection of entanglement using the partial transpose operation is also demonstrated without performing quantum state tomography.
In this paper, we propose and analyze an experimental scheme for directly observing the noncommutativity of the position and the momentum operators using single-photon quantum interference.
We experimentally demonstrate the non-monotonic dependence of many-particle interference signals on the particles mutual distinguishability. Such non-monotonicity is a generic feature of the quantum to classical transition in multiparticle systems.
We report the first experimental realization of an approximate partial transpose for photonic two-qubit systems. Direct detection of entanglement, i.e., without performing quantum state tomography, using the partial transpose operation, is also demonstrated.
We investigate approximating the universal transpose of quantum states of two-level systems (qubits) using the method known as the structural physical approximation to positive maps. We also report its experimental implementation in linear optics.
We report experimental verification of the commutation relation for Pauli spin operators using the single-photon polarization state. The experimental quantum operation corresponding to the commutator, [σz,σx]=kσy, showed process fidelity of 0.94 compared to the ideal σy operation and |k| is determined to be 2.12±0.18.
In the Aharonov-Albert-Vaidman (AAV) weak measurement, it is assumed that the measuring device or the pointer is in a quantum mechanical pure state. In reality, however, it is often not the case. In this paper, we generalize the AAV weak measurement scheme to include more generalized situations in which the measuring device is in a mixed state. We also report an optical implementation of the weak...
Coherence properties of the photon pair generated via spontaneous parametric down-conversion pumped by a multi-mode cw diode laser are studied with a Mach-Zehnder interferometer. Each photon of the pair enters a different input port of the interferometer and the biphoton coherence properties are studied with a two-photon detector placed at one output port. When the photon pair simultaneously enters...
We report the observation of the photonic de Broglie wave for a pair of photons, generated by spontaneous parametric down-conversion, that are not photon number-path entangled. The experimental and theoretical results suggest that the photonic de Broglie wave is, in fact, not related to the entanglement of the photons, rather it is related to the indistinguishable pathways established by the measurement...
We demonstrate the conditional reversal of a weak quantum measurement on a photonic qubit. The state recovery fidelity, determined by quantum process tomography, is shown to be over 94% for partial-collapse strength up to 0.9. We also experimentally study information gain due to the weak measurement and discuss the role of the reversing operation as an information erasure.
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