Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

AIP conference proceedings

Process Characterization of Experimental Photonic One-Way Quantum Computing

Yuuki Tokunaga, Shin Kuwashiro, Takashi Yamamoto, Masato Koashi, Nobuyuki Imoto, Alexander I. Lvovsky

Published Jan 1, 2009• 0 citations
Publisher

Abstract

We demonstrate process characterization of basic gates of an optical cluster‐state quantum computing. We present complete process tomography of a single‐qubit gate and evaluate the bounds on the process fidelity of a two‐qubit gate.
DOI
10.1063/1.3131373

Related papers

Process characterization of experimental photonic one-way quantum computing

Yuuki Tokunaga, Shin Kuwashiro, Takashi Yamamoto +2 more

We demonstrate process characterization of basic gates of an optical cluster-state quantum computing. We present complete process tomography of a single-qubit gate and evaluate the bounds on the process fidelity of a two-qubit gate.

Conference on Lasers and Electro-Optics•May 4, 2008•0 citations

Process tomography of elementary gates in optical one-way quantum computing

Yuuki Tokunaga, S. Okamoto, Rikizo Ikuta +5 more

We demonstrate quantum process tomography of experimental photonic one‐way quantum computing. We investigate one‐qubit rotation gates and the two‐qubit controlled‐phase gate and the process matrix is derived from the maximally likelihood estimation. From the completely reconstructed process matrices, we can evaluate several gate performances such as process fidelity, purity, and entanglement capability.

AIP conference proceedings•Jan 1, 2011•0 citations

Experimental characterization of universal one-way quantum computing

B A Bell, Mark Tame, A S Clark +3 more

We report the characterization of a universal set of logic gates for one-way quantum computing using a four-photon ‘star’ cluster state generated by fusing photons from two independent photonic crystal fibre sources. We obtain a fidelity for the cluster state of 0.66 ± 0.01 with respect to the ideal case. We perform quantum process tomography to completely characterize a controlled-NOT, Hadamard and T gate all on the same compact entangled resource. Together, these operations make up a universal set of gates such that arbitrary quantum logic can be efficiently constructed from combinations of them. We find process fidelities with respect to the ideal cases of 0.64 ± 0.01 for the CNOT, 0.67 ± 0.03 for the Hadamard and 0.76 ± 0.04 for the T gate. The characterization of these gates enables the simulation of larger protocols and algorithms. As a basic example, we simulate a Swap gate consisting of three concatenated CNOT gates. Our work provides some pragmatic insights into the prospects for building up to a fully scalable and fault-tolerant one-way quantum computer with photons in realistic conditions.

arXiv:1305.0212•New Journal of Physics•May 20, 2013•26 citations

Experimental investigation of pulsed entangled photons and photonic quantum channels

Yoshihiro Nambu, Koji Usami, Akihisa Tomita +5 more

The development of key devices and systems in quantum information technology, such as entangled particle sources, quantum gates and quantum cryptographic systems, requires a reliable and well-established method for characterizing how well the devices or systems work. We report our recent work on experimental characterization of pulsed entangled photonic states and photonic quantum channels, using the methods of state and process tomography. By using state tomography, we could reliably evaluate the states generated from a two-photon source under development and develop a highly entangled pulsed photon source. We are also devoted to characterization of single-qubit and two-qubit photonic quantum channels. Characterization of typical single-qubit decoherence channels has been demonstrated using process tomography. Characterization of two-qubit channels, such as classically correlated channels and quantum mechanically correlated channels is under investigation. These characterization techniques for quantum states and quantum processes will be useful for developing photonic quantum devices and for improving their performances.

arXiv:quant-ph/0210147•Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Sep 11, 2002•14 citations

Quantum Process Tomography of a Controlled-NOT Gate

Jeremy L. O’Brien, Geoff J. Pryde, Alexei Gilchrist +4 more

We demonstrate complete characterization of a two-qubit entangling process--a linear optics controlled-NOT gate operating with coincident detection--by quantum process tomography. We use a maximum-likelihood estimation to convert the experimental data into a physical process matrix. The process matrix allows an accurate prediction of the operation of the gate for arbitrary input states and a calculation of gate performance measures such as the average gate fidelity, average purity, and entangling capability of our gate, which are 0.90, 0.83, and 0.73, respectively.

arXiv:quant-ph/0402166•Physical Review Letters•Aug 20, 2004•499 citations

Realization and characterization of a 2-photon 4-qubit linear cluster state

Giuseppe Vallone, Enrico Pomarico, Paolo Mataloni +2 more

Cluster states, recently introduced as a fundamental resource for one-way quantum computation, represent genuine multiqubits entangled states. The one-way model is based on the initial preparation of entangled qubits in the cluster state, followed by single qubits measurements and feed-forwards. All the difficulties present in the standard computation model, for instance the implementation of two qubits gates, are transferred in the one-way model to the state preparation.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 1, 2007•2 citations
We report the characterization of a universal set of logic gates for one-way quantum computing using a four-photon ‘star’ cluster state generated by fusing photons from two independent photonic crystal fibre sources. We obtain a fidelity for the cluster state of 0.66 ± 0.01 with respect to the ideal case. We perform quantum process tomography to completely characterize a controlled-NOT, Hadamard and T gate all on the same compact entangled resource. Together, these operations make up a universal set of gates such that arbitrary quantum logic can be efficiently constructed from combinations of them. We find process fidelities with respect to the ideal cases of 0.64 ± 0.01 for the CNOT, 0.67 ± 0.03 for the Hadamard and 0.76 ± 0.04 for the T gate. The characterization of these gates enables the simulation of larger protocols and algorithms. As a basic example, we simulate a Swap gate consisting of three concatenated CNOT gates. Our work provides some pragmatic insights into the prospects for building up to a fully scalable and fault-tolerant one-way quantum computer with photons in realistic conditions.
The development of key devices and systems in quantum information technology, such as entangled particle sources, quantum gates and quantum cryptographic systems, requires a reliable and well-established method for characterizing how well the devices or systems work. We report our recent work on experimental characterization of pulsed entangled photonic states and photonic quantum channels, using the methods of state and process tomography. By using state tomography, we could reliably evaluate the states generated from a two-photon source under development and develop a highly entangled pulsed photon source. We are also devoted to characterization of single-qubit and two-qubit photonic quantum channels. Characterization of typical single-qubit decoherence channels has been demonstrated using process tomography. Characterization of two-qubit channels, such as classically correlated channels and quantum mechanically correlated channels is under investigation. These characterization techniques for quantum states and quantum processes will be useful for developing photonic quantum devices and for improving their performances.
We demonstrate complete characterization of a two-qubit entangling process--a linear optics controlled-NOT gate operating with coincident detection--by quantum process tomography. We use a maximum-likelihood estimation to convert the experimental data into a physical process matrix. The process matrix allows an accurate prediction of the operation of the gate for arbitrary input states and a calculation of gate performance measures such as the average gate fidelity, average purity, and entangling capability of our gate, which are 0.90, 0.83, and 0.73, respectively.