An equivalent circuit model of nanowire diodes is introduced. Because nanowire diodes inevitably involve a metal-semiconductor-metal structure, they consist of two metal-semiconductor contacts and one resistor in betw...
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We demonstrate how using two-qubit composite rotations a high fidelity controlled-NOT (CNOT) gate can be constructed, even when the strength of the interaction between qubits is not accurately known. We focus on the e...
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We demonstrate how using two-qubit composite rotations a high fidelity controlled-NOT (CNOT) gate can be constructed, even when the strength of the interaction between qubits is not accurately known. We focus on the exchange interaction oscillation in silicon based solid-state architectures with a Heisenberg Hamiltonian. This method easily applies to a general two-qubit Hamiltonian. We show how the robust CNOT gate can achieve a very high fidelity when a single application of the composite rotations is combined with a modest level of Hamiltonian characterization. Operating the robust CNOT gate in a suitably characterized system means concatenation of the composite pulse is unnecessary, hence reducing operation time, and ensuring the gate operates below the threshold required for fault-tolerant quantum computation.
quantum key distribution (QKD) can be used to generate secret keys between two distant parties. Even though QKD has been proven unconditionally secure against eavesdroppers with unlimited computation power, practical ...
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quantum key distribution (QKD) can be used to generate secret keys between two distant parties. Even though QKD has been proven unconditionally secure against eavesdroppers with unlimited computation power, practical implementations of QKD may contain loopholes that may lead to the generated secret keys being compromised. In this paper, we propose a phase-remapping attack targeting two practical bidirectional QKD systems (the “plug-and-play” system and the Sagnac system). We showed that if the users of the systems are unaware of our attack, the final key shared between them can be compromised in some situations. Specifically, we showed that, in the case of the Bennett-Brassard 1984 (BB84) protocol with ideal single-photon sources, when the quantum bit error rate (QBER) is between 14.6% and 20%, our attack renders the final key insecure, whereas the same range of QBER values has been proved secure if the two users are unaware of our attack; also, we demonstrated three situations with realistic devices where positive key rates are obtained without the consideration of Trojan horse attacks but in fact no key can be distilled. We remark that our attack is feasible with only current technology. Therefore, it is very important to be aware of our attack in order to ensure absolute security. In finding our attack, we minimize the QBER over individual measurements described by a general POVM, which has some similarity with the standard quantum state discrimination problem.
We predict the spatial localization of multiple wavelength components in the form of stationary polychromatic gap solitons and dynamic multi-gap breathers, and observe experimentally tunable spatio-spectral trapping o...
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ZnO films were deposited on c-Al 2 O 3 using pulsed laser deposition both with and without N 2 in the growth ambient. X-ray diffraction revealed poorer crystal quality and surface morphology for one-step growths with ...
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We investigate two-way and one-way single-photon quantum key distribution (QKD) protocols in the presence of loss introduced by the quantum channel. Our analysis is based on a simple precondition for secure QKD in eac...
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We investigate two-way and one-way single-photon quantum key distribution (QKD) protocols in the presence of loss introduced by the quantum channel. Our analysis is based on a simple precondition for secure QKD in each case. In particular, the legitimate users need to prove that there exists no separable state (in the case of two-way QKD), or that there exists no quantum state having a symmetric extension (one-way QKD), that is compatible with the available measurements results. We show that both criteria can be formulated as a convex optimization problem known as a semidefinite program, which can be efficiently solved. Moreover, we prove that the solution to the dual optimization corresponds to the evaluation of an optimal witness operator that belongs to the minimal verification set of them for the given two-way (or one-way) QKD protocol. A positive expectation value of this optimal witness operator states that no secret key can be distilled from the available measurements results. We apply such analysis to several well-known single-photon QKD protocols under losses.
We demonstrate a mid-infrared laser source tunable between 3.2 mum and 4.8 mum with an average output power of more than 1 mW. The spectral bandwidth of up to 325 nm supports sub- 60-fs pulses.
ISBN:
(纸本)1557528349
We demonstrate a mid-infrared laser source tunable between 3.2 mum and 4.8 mum with an average output power of more than 1 mW. The spectral bandwidth of up to 325 nm supports sub- 60-fs pulses.
A broadband fiber-based femtosecond laser source, tunable in the mid-IR between 3.2 μm and 4.8 μm, exhibiting a maximum output power of more than 1 mW, and a conversion efficiency of more than 30%, is demonstrated. ...
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A broadband fiber-based femtosecond laser source, tunable in the mid-IR between 3.2 μm and 4.8 μm, exhibiting a maximum output power of more than 1 mW, and a conversion efficiency of more than 30%, is demonstrated. For experiment commercially available Er:fiber two-branch amplifier laser system is used.
Design innovations to overcome the shortcomings of a wireless power transmission sheet made with plastic MEMS switches and OFET for printable low-cost electronics are shown. The mixed circuits of MEMS switches and OFE...
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Design innovations to overcome the shortcomings of a wireless power transmission sheet made with plastic MEMS switches and OFET for printable low-cost electronics are shown. The mixed circuits of MEMS switches and OFETs with two different frequencies reduce the number of coil sheets form 2 to 1. OFET level-shifters, with the current-source loads with enhancement/depletion mixed threshold voltages realized by controlling the back-gate voltage, bridge the operation voltage gap between silicon VLSIs (below 5 V) and OFETs/MEMS (above 40 V).
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