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Hyperparallel quantum information processing outperforms its traditional parallel one in terms of channel capacity, low loss rate, and processing speed. We present a way for implementing a robust hyper-parallel optical controlled-phase-flip…

Quantum Physics · Physics 2020-08-05 Hai-Rui Wei , Yan-Bei Zheng , Ming Hua , Guo-Fu Xu

Linear optics quantum logic gates are the best tool to generate multi-photon entanglement. Simplifying a recent approach [Phys. Rev. A 65, 062324; Phys. Rev. A 66, 024308] we were able to implement the conditional phase gate with only one…

Quantum Physics · Physics 2009-11-11 Nikolai Kiesel , Christian Schmid , Ulrich Weber , Rupert Ursin , Harald Weinfurter

The ability to engineer high-fidelity gates on quantum processors in the presence of systematic errors remains the primary barrier to achieving quantum advantage. Quantum optimal control methods have proven effective in experimentally…

Quantum Physics · Physics 2021-03-30 Thomas Propson , Brian E. Jackson , Jens Koch , Zachary Manchester , David I. Schuster

We report the first experimental demonstration of an optical quantum controlled-NOT gate without any path interference, where the two interacting path interferometers of the original proposals (Phys. Rev. A {\bf 66}, 024308 (2001), Phys.…

Quantum Physics · Physics 2009-11-11 Ryo Okamoto , Holger F. Hofmann , Shigeki Takeuchi , Keiji Sasaki

Time-bin qubits, where information is encoded in a single photon at different times, have been widely used in optical fiber and waveguide based quantum communications. With the recent developments in distributed quantum computation, it is…

Quantum optimal control for gate optimization aims to provide accurate, robust, and fast pulse sequences to achieve gate fidelities on quantum systems below the error correction threshold. Many methods have been developed and successfully…

Quantum Physics · Physics 2025-06-05 Dirk Heimann , Felix Wiebe , Tahereh Abad , Elie Mounzer , Tangyou Huang , Frank Kirchner , Shivesh Kumar

We present here an all--optical scheme for the experimental realization of a quantum phase gate. It is based on the polarization degree of freedom of two travelling single photon wave-packets and exploits giant Kerr nonlinearities that can…

Quantum Physics · Physics 2009-11-10 Carlo Ottaviani , David Vitali , Maurizio Artoni , Francesco Cataliotti , Paolo Tombesi

We demonstrate high fidelity entangling quantum gates within a chain of five trapped ion qubits by optimally shaping optical fields that couple to multiple collective modes of motion. We individually address qubits with segmented optical…

Quantum Physics · Physics 2014-05-20 T. Choi , S. Debnath , T. A. Manning , C. Figgatt , Z. -X. Gong , L. -M. Duan , C. Monroe

The controlled-NOT gate and controlled square-root NOT gate play an important role in quantum algorithm. This article reports the experimental results of these two universal quantum logic gates (controlled square-root NOT gate and…

Quantum Physics · Physics 2007-05-23 Daxiu Wei , Xiaodong Yang , Jun Luo , Xianping Sun , Xizhi Zeng , Maili Liu , Shangwu Ding

The fundamental gates of linear optics quantum computation are realized by using single photons sources, linear optics and photon counters. Success of these gates is conditioned on the pattern of photons detected without using feedback.…

Quantum Physics · Physics 2009-11-10 E. Knill

Quantum optimal control represents a powerful technique to enhance the performance of quantum experiments by engineering the controllable parameters of the Hamiltonian. However, the computational overhead for the necessary optimization of…

Recently it was realized that linear optics and photo-detectors with feedback can be used for theoretically efficient quantum information processing. The first of three steps toward efficient linear optics quantum computation (eLOQC) was to…

Quantum Physics · Physics 2013-05-29 E. Knill

In this paper, with the weak cross-Kerr nonlinearity, we first present a special experimental scheme called C-path gate with which the realization of all possible bipartite POVMs of two-photon polarization states can be simpler and nearly…

Quantum Physics · Physics 2009-02-26 Qing Lin , Jian Li

Universal quantum gates lie at the heart of designing quantum computer. We construct two compact quantum circuits to implement post-selected controlled-phase-flip (CPF) gate and Toffoli gate with linear optics assisted by one and two single…

Quantum Physics · Physics 2022-11-18 Wen-Qiang Liu , Hai-Rui Wei

All-linear-optical scheme for fully featured quantum router is presented. This device directs the signal photonic qubit according to the state of one control photonic qubit. In the introduction we formulate the list of requirements imposed…

Quantum Physics · Physics 2013-07-01 Karel Lemr , Karol Bartkiewicz , Antonín Černoch , Jan Soubusta

We report the first experimental demonstration of an optical controlled-NOT gate constructed entirely in fibre. We operate the gate using two heralded optical fibre single photon sources and find an average logical fidelity of 90% and an…

The promise of tremendous computational power, coupled with the development of robust error-correcting schemes, has fuelled extensive efforts to build a quantum computer. The requirements for realizing such a device are confounding:…

Quantum Physics · Physics 2011-08-17 J L O'Brien , G J Pryde , A G White , T C Ralph , D Branning

We design optimal interferometric schemes for implementation of two-qubit linear optical quantum filters diagonal in the computational basis. The filtering is realized by interference of the two photons encoding the qubits in a multiport…

Quantum Physics · Physics 2021-06-16 Jaromír Fiurášek , Robert Stárek , Michal Mičuda

We propose a one-step scheme to implement a multiqubit controlled phase gate of one qubit simultaneously controlling multiple qubits with three-level atoms at distant nodes in coupled cavity arrays. The selective qubit-qubit couplings are…

Quantum Physics · Physics 2015-06-18 Hong-Fu Wang , Ai-Dong Zhu , Shou Zhang

Entangling operations are among the most important primitive gates employed in quantum computing and it is crucial to ensure high-fidelity implementations as systems are scaled up. We experimentally realize and characterize a simple scheme…