The Experts below are selected from a list of 10215 Experts worldwide ranked by ideXlab platform
Karel Lemr - One of the best experts on this subject based on the ideXlab platform.
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implementation of an efficient linear optical quantum router
Scientific Reports, 2018Co-Authors: Karol Bartkiewicz, Antonin Cernoch, Karel LemrAbstract:For several decades, scientists have been aware of significant benefits allowing quantum information processing technologies to surpass their classical counterparts. Recent technological development allows these benefits to be tested experimentally and in some cases also implemented in practical devices. So far the majority of experimental quantum networks was limited to peer-to-peer communications between two parties. Practical implementation of quantum communications networks, however, needs to address the problem of scalability to serve large numbers of users. Similarly to classical computer networks, their quantum counterparts would require routing protocols to direct the signal from its source to destination. Devices implementing these routing protocols are called quantum routers and have recently been subject of an intense research. In this paper, we report on experimental implementation of a linear-optical quantum router. Our device allows single-photon polarization-encoded Qubits to be routed coherently into two spatial output modes depending on the state of two identical Control Qubits. The polarization qubit state of the routed photon is maintained during the routing operation. The success probability of our scheme can be increased up to 25% making it the most efficient linear-optical quantum router developed to this date.
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implementation of an efficient linear optical quantum router
arXiv: Quantum Physics, 2018Co-Authors: Karol Bartkiewicz, Antonin Cernoch, Karel LemrAbstract:In this paper, we report on experimental implementation of a linear-optical quantum router. Our device allows single-photon polarization-encoded Qubits to be routed coherently into two spatial output modes depending on the state of two identical Control Qubits. The polarization qubit state of the routed photon is maintained during the routing operation. The success probability of our scheme can be increased up to 25% making it the most efficient linear-optical quantum router known to this date.
Karol Bartkiewicz - One of the best experts on this subject based on the ideXlab platform.
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implementation of an efficient linear optical quantum router
Scientific Reports, 2018Co-Authors: Karol Bartkiewicz, Antonin Cernoch, Karel LemrAbstract:For several decades, scientists have been aware of significant benefits allowing quantum information processing technologies to surpass their classical counterparts. Recent technological development allows these benefits to be tested experimentally and in some cases also implemented in practical devices. So far the majority of experimental quantum networks was limited to peer-to-peer communications between two parties. Practical implementation of quantum communications networks, however, needs to address the problem of scalability to serve large numbers of users. Similarly to classical computer networks, their quantum counterparts would require routing protocols to direct the signal from its source to destination. Devices implementing these routing protocols are called quantum routers and have recently been subject of an intense research. In this paper, we report on experimental implementation of a linear-optical quantum router. Our device allows single-photon polarization-encoded Qubits to be routed coherently into two spatial output modes depending on the state of two identical Control Qubits. The polarization qubit state of the routed photon is maintained during the routing operation. The success probability of our scheme can be increased up to 25% making it the most efficient linear-optical quantum router developed to this date.
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implementation of an efficient linear optical quantum router
arXiv: Quantum Physics, 2018Co-Authors: Karol Bartkiewicz, Antonin Cernoch, Karel LemrAbstract:In this paper, we report on experimental implementation of a linear-optical quantum router. Our device allows single-photon polarization-encoded Qubits to be routed coherently into two spatial output modes depending on the state of two identical Control Qubits. The polarization qubit state of the routed photon is maintained during the routing operation. The success probability of our scheme can be increased up to 25% making it the most efficient linear-optical quantum router known to this date.
Antonin Cernoch - One of the best experts on this subject based on the ideXlab platform.
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implementation of an efficient linear optical quantum router
Scientific Reports, 2018Co-Authors: Karol Bartkiewicz, Antonin Cernoch, Karel LemrAbstract:For several decades, scientists have been aware of significant benefits allowing quantum information processing technologies to surpass their classical counterparts. Recent technological development allows these benefits to be tested experimentally and in some cases also implemented in practical devices. So far the majority of experimental quantum networks was limited to peer-to-peer communications between two parties. Practical implementation of quantum communications networks, however, needs to address the problem of scalability to serve large numbers of users. Similarly to classical computer networks, their quantum counterparts would require routing protocols to direct the signal from its source to destination. Devices implementing these routing protocols are called quantum routers and have recently been subject of an intense research. In this paper, we report on experimental implementation of a linear-optical quantum router. Our device allows single-photon polarization-encoded Qubits to be routed coherently into two spatial output modes depending on the state of two identical Control Qubits. The polarization qubit state of the routed photon is maintained during the routing operation. The success probability of our scheme can be increased up to 25% making it the most efficient linear-optical quantum router developed to this date.
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implementation of an efficient linear optical quantum router
arXiv: Quantum Physics, 2018Co-Authors: Karol Bartkiewicz, Antonin Cernoch, Karel LemrAbstract:In this paper, we report on experimental implementation of a linear-optical quantum router. Our device allows single-photon polarization-encoded Qubits to be routed coherently into two spatial output modes depending on the state of two identical Control Qubits. The polarization qubit state of the routed photon is maintained during the routing operation. The success probability of our scheme can be increased up to 25% making it the most efficient linear-optical quantum router known to this date.
R Gerritsma - One of the best experts on this subject based on the ideXlab platform.
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high fidelity method for a single step n bit toffoli gate in trapped ions
Physical Review A, 2021Co-Authors: Juan Diego Arias Espinoza, Koen Groenland, M Mazzanti, Kareljan Schoutens, R GerritsmaAbstract:Conditional multiqubit gates are a key component for elaborate quantum algorithms. In a recent work, Rasmussen et al. [Phys. Rev. A 101, 022308 (2020)] proposed an efficient single-step method for a prototypical multiqubit gate, a Toffoli gate, based on a combination of Ising interactions between Control Qubits and an appropriate driving field on a target qubit. Trapped ions are a natural platform to implement this method, since Ising interactions mediated by phonons have been demonstrated in increasingly large ion crystals. However, the simultaneous application of these interactions and the driving field required for the gate results in undesired entanglement between the Qubits and the motion of the ions, reducing the gate fidelity. In this work, we propose a solution based on adiabatic switching of these phonon-mediated Ising interactions. We study the effects of imperfect ground-state cooling and use spin-echo techniques to undo unwanted phase accumulation in the achievable fidelities. For gates coupling to all axial modes of a linear crystal, we calculate high-fidelity $(g99%)$ $N$-qubit rotations with $N=3--7$ ions cooled to their ground state of motion and a gate time below 1 ms. Finally, we study the effect of laser intensity fluctuations and find that the proposed gate requires intensity stabilization with subpercentage noise levels. The high fidelities obtained also for large crystals could make the gate competitive with gate-decomposed, multistep variants of the $N$-qubit Toffoli gate, at the expense of requiring ground-state cooling of the ion crystal.
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signal processing techniques for efficient compilation of Controlled rotations in trapped ions
New Journal of Physics, 2020Co-Authors: Koen Groenland, Kareljan Schoutens, Freek Witteveen, R GerritsmaAbstract:Quantum logic gates with many Control Qubits are essential in many quantum algorithms, but remain challenging to perform in current experiments. Trapped ion quantum computers natively feature a different type of entangling operation, namely the Molmer-Sorensen (MS) gate which effectively applies an Ising interaction to all Qubits at the same time. We consider a sequence of equal all-to-all MS operations, interleaved with single qubit gates that act only on one special qubit. Using a connection with quantum signal processing techniques, we find that it is possible to perform an arbitray SU(2) rotation on the special qubit if and only if all other Qubits are in the state |1>. Such Controlled rotation gates with N-1 Control Qubits require 2N applications of the MS gate, and can be mapped to a conventional Toffoli gate by demoting a single qubit to ancilla.
Koen Groenland - One of the best experts on this subject based on the ideXlab platform.
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high fidelity method for a single step n bit toffoli gate in trapped ions
Physical Review A, 2021Co-Authors: Juan Diego Arias Espinoza, Koen Groenland, M Mazzanti, Kareljan Schoutens, R GerritsmaAbstract:Conditional multiqubit gates are a key component for elaborate quantum algorithms. In a recent work, Rasmussen et al. [Phys. Rev. A 101, 022308 (2020)] proposed an efficient single-step method for a prototypical multiqubit gate, a Toffoli gate, based on a combination of Ising interactions between Control Qubits and an appropriate driving field on a target qubit. Trapped ions are a natural platform to implement this method, since Ising interactions mediated by phonons have been demonstrated in increasingly large ion crystals. However, the simultaneous application of these interactions and the driving field required for the gate results in undesired entanglement between the Qubits and the motion of the ions, reducing the gate fidelity. In this work, we propose a solution based on adiabatic switching of these phonon-mediated Ising interactions. We study the effects of imperfect ground-state cooling and use spin-echo techniques to undo unwanted phase accumulation in the achievable fidelities. For gates coupling to all axial modes of a linear crystal, we calculate high-fidelity $(g99%)$ $N$-qubit rotations with $N=3--7$ ions cooled to their ground state of motion and a gate time below 1 ms. Finally, we study the effect of laser intensity fluctuations and find that the proposed gate requires intensity stabilization with subpercentage noise levels. The high fidelities obtained also for large crystals could make the gate competitive with gate-decomposed, multistep variants of the $N$-qubit Toffoli gate, at the expense of requiring ground-state cooling of the ion crystal.
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signal processing techniques for efficient compilation of Controlled rotations in trapped ions
New Journal of Physics, 2020Co-Authors: Koen Groenland, Kareljan Schoutens, Freek Witteveen, R GerritsmaAbstract:Quantum logic gates with many Control Qubits are essential in many quantum algorithms, but remain challenging to perform in current experiments. Trapped ion quantum computers natively feature a different type of entangling operation, namely the Molmer-Sorensen (MS) gate which effectively applies an Ising interaction to all Qubits at the same time. We consider a sequence of equal all-to-all MS operations, interleaved with single qubit gates that act only on one special qubit. Using a connection with quantum signal processing techniques, we find that it is possible to perform an arbitray SU(2) rotation on the special qubit if and only if all other Qubits are in the state |1>. Such Controlled rotation gates with N-1 Control Qubits require 2N applications of the MS gate, and can be mapped to a conventional Toffoli gate by demoting a single qubit to ancilla.