The Experts below are selected from a list of 1950 Experts worldwide ranked by ideXlab platform
Pierre Rouchon - One of the best experts on this subject based on the ideXlab platform.
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Design and stability of discrete-time quantum Filters with measurement imperfections
2012Co-Authors: Abhinav Somaraju, Igor Dotsenko, Clément Sayrin, Pierre RouchonAbstract:This work considers the theory underlying a discrete-time quantum Filter recently used in a quantum feedback experiment. It proves that this Filter taking into account decoherence and measurement errors is optimal and stable. We present the general framework underlying the Filter and show that it corresponds to a recursive expression of the least-square optimal estimation of the density operator in the presence of measurement imperfections. By measurement imperfections, we mean in a very general sense unread measurement performed by the environment (decoherence) and active measurement performed by non-ideal detectors. However, we assume to know precisely all the Kraus operators and also the detection error rates. Such recursive expressions combine well known methods from quantum Filtering theory and classical probability theory (Bayes' law). We then demonstrate that such a recursive Filter is always stable with respect to its initial condition: the fidelity between the optimal Filter State (when the initial Filter State coincides with the real quantum State) and the Filter State (when the initial Filter State is arbitrary) is a sub-martingale.
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ACC - Design and stability of discrete-time quantum Filters with measurement imperfections
2012 American Control Conference (ACC), 2012Co-Authors: Abhinav Somaraju, Igor Dotsenko, Clément Sayrin, Pierre RouchonAbstract:This work considers the theory underlying a discrete-time quantum Filter recently used in a quantum feedback experiment. It proves that this Filter taking into account decoherence and measurement errors is optimal and stable. We present the general framework underlying the Filter and show that it corresponds to a recursive expression of the least-square optimal estimation of the density operator in the presence of measurement imperfections. By measurement imperfections, we mean in a very general sense unread measurement performed by the environment (decoherence) and active measurement performed by non-ideal detectors. However, we assume to know precisely all the Kraus operators and also the detection error rates. Such recursive expressions combine well known methods from quantum Filtering theory and classical probability theory (Bayes' law). We then demonstrate that such a recursive Filter is always stable with respect to its initial condition: the fidelity between the optimal Filter State (when the initial Filter State coincides with the real quantum State) and the Filter State (when the initial Filter State is arbitrary) is a sub-martingale.
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On stability of continuous-time quantum Filters
2011Co-Authors: Hadis Amini, Mazyar Mirrahimi, Pierre RouchonAbstract:We prove that the fidelity between the quantum State governed by a continuous time stochastic master equation driven by a Wiener process and its associated quantum-Filter State is a sub-martingale. This result is a generalization to non-pure quantum States where fidelity does not coincide in general with a simple Frobenius inner product. This result implies the stability of such Filtering process but does not necessarily ensure the asymptotic convergence of such quantum-Filters.
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Design and Stability of Discrete-Time Quantum Filters with Measurement Imperfections
arXiv: Mathematical Physics, 2011Co-Authors: Abhinav Somaraju, Igor Dotsenko, Clément Sayrin, Pierre RouchonAbstract:This work considers the theory underlying a discrete-time quantum Filter recently used in a quantum feedback experiment. It proves that this Filter taking into account decoherence and measurement errors is optimal and stable. We present the general framework underlying this Filter and show that it corresponds to a recursive expression of the least-square optimal estimation of the density operator in the presence of measurement imperfections. By measurement imperfections, we mean in a very general sense unread measurement performed by the environment (decoherence) and active measurement performed by non-ideal detectors. However, we assume to know precisely all the Kraus operators and also the detection error rates. Such recursive expressions combine well known methods from quantum Filtering theory and classical probability theory (Bayes' law). We then demonstrate that such a recursive Filter is always stable with respect to its initial condition: the fidelity between the optimal Filter State (when the initial Filter State coincides with the real quantum State) and the Filter State (when the initial Filter State is arbitrary) is a sub-martingale.
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CDC-ECE - On stability of continuous-time quantum Filters
IEEE Conference on Decision and Control and European Control Conference, 2011Co-Authors: Hadis Amini, Mazyar Mirrahimi, Pierre RouchonAbstract:We prove that the fidelity between the quantum State governed by a continuous time stochastic master equation driven by a Wiener process and its associated quantum-Filter State is a sub-martingale. This result is a generalization to non-pure quantum States where fidelity does not coincide in general with a simple Frobenius inner product. This result implies the stability of such Filtering process but does not necessarily ensure the asymptotic convergence of such quantum-Filters.
Tolga Soyata - One of the best experts on this subject based on the ideXlab platform.
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energy awareness for supercapacitors using kalman Filter State of charge tracking
Journal of Power Sources, 2015Co-Authors: Andrew Nadeau, Moeen Hassanalieragh, Gaurav Sharma, Tolga SoyataAbstract:Abstract Among energy buffering alternatives, supercapacitors can provide unmatched efficiency and durability. Additionally, the direct relation between a supercapacitor's terminal voltage and stored energy can improve energy awareness. However, a simple capacitive approximation cannot adequately represent the stored energy in a supercapacitor. It is shown that the three branch equivalent circuit model provides more accurate energy awareness. This equivalent circuit uses three capacitances and associated resistances to represent the supercapacitor's internal SOC (State-of-charge). However, the SOC cannot be determined from one observation of the terminal voltage, and must be tracked over time using inexact measurements. We present: 1) a Kalman Filtering solution for tracking the SOC; 2) an on-line system identification procedure to efficiently estimate the equivalent circuit's parameters; and 3) experimental validation of both parameter estimation and SOC tracking for 5 F, 10 F, 50 F, and 350 F supercapacitors. Validation is done within the operating range of a solar powered application and the associated power variability due to energy harvesting. The proposed techniques are benchmarked against the simple capacitive model and prior parameter estimation techniques, and provide a 67% reduction in root-mean-square error for predicting usable buffered energy.
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Energy awareness for supercapacitors using Kalman Filter State-of-charge tracking ☆ ☆☆
Journal of Power Sources, 2015Co-Authors: Andrew Nadeau, Moeen Hassanalieragh, Gaurav Sharma, Tolga SoyataAbstract:Abstract Among energy buffering alternatives, supercapacitors can provide unmatched efficiency and durability. Additionally, the direct relation between a supercapacitor's terminal voltage and stored energy can improve energy awareness. However, a simple capacitive approximation cannot adequately represent the stored energy in a supercapacitor. It is shown that the three branch equivalent circuit model provides more accurate energy awareness. This equivalent circuit uses three capacitances and associated resistances to represent the supercapacitor's internal SOC (State-of-charge). However, the SOC cannot be determined from one observation of the terminal voltage, and must be tracked over time using inexact measurements. We present: 1) a Kalman Filtering solution for tracking the SOC; 2) an on-line system identification procedure to efficiently estimate the equivalent circuit's parameters; and 3) experimental validation of both parameter estimation and SOC tracking for 5 F, 10 F, 50 F, and 350 F supercapacitors. Validation is done within the operating range of a solar powered application and the associated power variability due to energy harvesting. The proposed techniques are benchmarked against the simple capacitive model and prior parameter estimation techniques, and provide a 67% reduction in root-mean-square error for predicting usable buffered energy.
Alexander M. Saletsky - One of the best experts on this subject based on the ideXlab platform.
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Spin-Filter State of Au-Co nanowires
EPJ Web of Conferences, 2018Co-Authors: E. M. Smelova, K. M. Tsysar, Alexander M. SaletskyAbstract:Our theoretical study reveals the dependence of quantum conductance of Au-Co nanowires on their atomic structure. The results show the emergence of spin-Filter State in one-dimensional Au-Co bimetallic nanowires. We found the existence of two transmission regime in Au-Co nanowires with low and high conductivity 1G0 and 2G0 for “zig-zag” and linear nanowire correspondingly. The study of transmission spectra of Au-Co nanowires reveals the control capability of spin transport regime by changing of bias voltage between bulk electrodes.
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Emergence of spin-Filter States in Pt-Fe nanowires.
Physical chemistry chemical physics : PCCP, 2014Co-Authors: E. M. Smelova, K. M. Tsysar, Alexander M. SaletskyAbstract:Our theoretical study predicts the emergence of a new spin-Filter State in one-dimensional Pt–Fe bimetallic nanowires. The results show the existence of two transmission States in contracted “zig-zag” Pt–Fe nanowires with low and high transmission 1G0 and 3G0, correspondingly, and one transmission State in linear stretched nanowires with conductance 2G0. Our first principle calculations revealed the dependence of quantum conductance of Pt–Fe nanowires on their geometry and atomic structure. Thus we found that nanowire stretching up to the interatomic distance of 2.3 A leads to the transition of the wire from a “zig-zag” to the linear configuration, leading to changes in the conductance properties of the wire, i.e. formation of a new spin-Filter State. Our study shows also the emergence of a magnetic transition from ferromagnetic to antiferromagnetic States under wire stretching. We found that the spin-Filter State exists only in “zig-zag” Pt–Fe nanowires in the ferromagnetic State. Moreover, the spin-polarization of quantum electron transport through Pt–Fe nanowires vanishes totally in linear stretched nanowires in an antiferromagnetic State. Our electronic structure calculation reveals the emergence of new hybridized States in the band structure of the Pt–Fe nanowire, which causes the formation of a new spin-Filter State.
Andrew Nadeau - One of the best experts on this subject based on the ideXlab platform.
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energy awareness for supercapacitors using kalman Filter State of charge tracking
Journal of Power Sources, 2015Co-Authors: Andrew Nadeau, Moeen Hassanalieragh, Gaurav Sharma, Tolga SoyataAbstract:Abstract Among energy buffering alternatives, supercapacitors can provide unmatched efficiency and durability. Additionally, the direct relation between a supercapacitor's terminal voltage and stored energy can improve energy awareness. However, a simple capacitive approximation cannot adequately represent the stored energy in a supercapacitor. It is shown that the three branch equivalent circuit model provides more accurate energy awareness. This equivalent circuit uses three capacitances and associated resistances to represent the supercapacitor's internal SOC (State-of-charge). However, the SOC cannot be determined from one observation of the terminal voltage, and must be tracked over time using inexact measurements. We present: 1) a Kalman Filtering solution for tracking the SOC; 2) an on-line system identification procedure to efficiently estimate the equivalent circuit's parameters; and 3) experimental validation of both parameter estimation and SOC tracking for 5 F, 10 F, 50 F, and 350 F supercapacitors. Validation is done within the operating range of a solar powered application and the associated power variability due to energy harvesting. The proposed techniques are benchmarked against the simple capacitive model and prior parameter estimation techniques, and provide a 67% reduction in root-mean-square error for predicting usable buffered energy.
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Energy awareness for supercapacitors using Kalman Filter State-of-charge tracking ☆ ☆☆
Journal of Power Sources, 2015Co-Authors: Andrew Nadeau, Moeen Hassanalieragh, Gaurav Sharma, Tolga SoyataAbstract:Abstract Among energy buffering alternatives, supercapacitors can provide unmatched efficiency and durability. Additionally, the direct relation between a supercapacitor's terminal voltage and stored energy can improve energy awareness. However, a simple capacitive approximation cannot adequately represent the stored energy in a supercapacitor. It is shown that the three branch equivalent circuit model provides more accurate energy awareness. This equivalent circuit uses three capacitances and associated resistances to represent the supercapacitor's internal SOC (State-of-charge). However, the SOC cannot be determined from one observation of the terminal voltage, and must be tracked over time using inexact measurements. We present: 1) a Kalman Filtering solution for tracking the SOC; 2) an on-line system identification procedure to efficiently estimate the equivalent circuit's parameters; and 3) experimental validation of both parameter estimation and SOC tracking for 5 F, 10 F, 50 F, and 350 F supercapacitors. Validation is done within the operating range of a solar powered application and the associated power variability due to energy harvesting. The proposed techniques are benchmarked against the simple capacitive model and prior parameter estimation techniques, and provide a 67% reduction in root-mean-square error for predicting usable buffered energy.
Chang-chieh Hang - One of the best experts on this subject based on the ideXlab platform.
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Non-smooth Lyapunov function-based global stabilization for quantum Filters
Automatica, 2012Co-Authors: Chang-chieh HangAbstract:This paper addresses the global stabilization problem for a class of quantum Filters via non-smooth Lyapunov functions. Due to the intrinsic symmetric topology of Filter State space, the smooth controls synthesized via the classical Lyapunov stochastic stability theory fail to obtain the global stabilizability because of the existence of the so-called antipodal eigenStates. As such, for the first time, we introduce a non-smooth Lyapunov-like theory for generic stochastic nonlinear systems, which includes a continuous Lyapunov-like theorem and a discontinuous Lyapunov-like theorem for stability in probability. Applying the non-smooth Lyapunov-like theory, switching control and continuous control in saturation form are constructed for the quantum Filters, with consideration of the sliding motion of Filter State. The non-smooth property enables these controls to deal with the symmetric topology of Filter State space and to solve the problem of global stabilization for quantum Filters. The eigenState-transferring is obtained as a special result, distinguishing these non-smooth Lyapunov-based controls from classical control approaches for quantum Filters. The effectiveness of the non-smooth Lyapunov-based controls is illustrated through the control design for the Spin-1/2 systems. Simulation results are presented and discussed to show the effectiveness of the controls.
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CDC - Non-smooth Lyapunov function-based global stabilization for 2-dimensional quantum Filters
49th IEEE Conference on Decision and Control (CDC), 2010Co-Authors: Chang-chieh HangAbstract:This paper addresses the global stabilization problem for 2-dimensional quantum Filters via non-smooth Lyapunov functions. Due to the symmetric topology of Filter State space, the smooth controls synthesized via smooth Lyapunov stochastic stability theory fail to obtain the global stabilizability. As such, for the first time, we introduce a non- smooth Lyapunov-like theory for generic stochastic nonlinear systems, which includes a continuous Lyapunov-like theorem and a discontinuous Lyapunov-like theorem for stability in probability. Applying the non-smooth Lyapunov-like theory, switching control and saturation-form control are constructed for 2-dimensional quantum Filters with the consideration of sliding motion. The non-smooth property enables these controls to deal with the symmetric topology of Filter State space and to globally asymptotically render the Filter State to the final desired State almost surely. The effectiveness of the proposed controls is illustrated through the control design for the Spin-1/2 system. Simulation results are presented and discussed.