The Experts below are selected from a list of 210363 Experts worldwide ranked by ideXlab platform
Arijit Raychowdhury - One of the best experts on this subject based on the ideXlab platform.
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synchronized charge oscillations in correlated electron systems
Scientific Reports, 2015Co-Authors: Nikhil Shukla, Abhinav Parihar, Eugene Freeman, Hanjong Paik, Greg Stone, Vijaykrishnan Narayanan, Venkatraman Gopalan, Roman Engelherbert, D G Schlom, Arijit RaychowdhuryAbstract:Strongly correlated phases exhibit collective carrier dynamics that if properly harnessed can enable novel functionalities and applications. In this article, we investigate the phenomenon of electrical oscillations in a prototypical MIT system, vanadium dioxide (VO2). We show that the key to such Oscillatory behaviour is the ability to induce and stabilize a non-hysteretic and spontaneously reversible phase transition using a negative feedback mechanism. Further, we investigate the synchronization and coupling dynamics of such VO2 based relaxation Oscillators and show, via experiment and simulation, that this coupled Oscillator system exhibits rich non-linear dynamics including charge oscillations that are synchronized in both frequency and phase. Our approach of harnessing a non-hysteretic reversible phase transition region is applicable to other correlated systems exhibiting metal-insulator transitions and can be a potential candidate for Oscillator based non-Boolean computing.
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synchronization of pairwise coupled identical relaxation Oscillators based on metal insulator phase transition devices a model study
Journal of Applied Physics, 2015Co-Authors: Abhinav Parihar, Nikhil Shukla, Suman Datta, Arijit RaychowdhuryAbstract:Computing with networks of synchronous Oscillators has attracted wide-spread attention as novel materials and device topologies have enabled realization of compact, scalable and low-power coupled Oscillatory systems. Of particular interest are compact and low-power relaxation Oscillators that have been recently demonstrated using MIT (metal-insulator-transition) devices using properties of correlated oxides. Further the computational capability of pairwise coupled relaxation Oscillators has also been shown to outperform traditional Boolean digital logic circuits. This paper presents an analysis of the dynamics and synchronization of a system of two such identical coupled relaxation Oscillators implemented with MIT devices. We focus on two implementations of the Oscillator: (a) a D-D configuration where complementary MIT devices (D) are connected in series to provide oscillations and (b) a D-R configuration where it is composed of a resistor (R) in series with a voltage-triggered state changing MIT device ...
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synchronization of pairwise coupled identical relaxation Oscillators based on metal insulator phase transition devices a model study
arXiv: Chaotic Dynamics, 2014Co-Authors: Abhinav Parihar, Nikhil Shukla, Suman Datta, Arijit RaychowdhuryAbstract:Computing with networks of synchronous Oscillators has attracted wide-spread attention as novel materials and device topologies have enabled realization of compact, scalable and low-power coupled Oscillatory systems. Of particular interest are compact and low-power relaxation Oscillators that have been recently demonstrated using MIT (metal- insulator-transition) devices using properties of correlated oxides. This paper presents an analysis of the dynamics and synchronization of a system of two such identical coupled relaxation Oscillators implemented with MIT devices. We focus on two implementations of the Oscillator: (a) a D-D configuration where complementary MIT devices (D) are connected in series to provide oscillations and (b) a D-R configuration where it is composed of a resistor (R) in series with a voltage-triggered state changing MIT device (D). The MIT device acts like a hysteresis resistor with different resistances in the two different states. The synchronization dynamics of such a system has been analyzed with purely charge based coupling using a resistive (Rc) and a capacitive (Cc) element in parallel. It is shown that in a D-D configuration symmetric, identical and capacitively coupled relaxation Oscillator system synchronizes to an anti-phase locking state, whereas when coupled resistively the system locks in phase. Further, we demonstrate that for certain range of values of Rc and Cc, a bistable system is possible which can have potential applications in associative computing. In D-R configuration, we demonstrate the existence of rich dynamics including non-monotonic flows and complex phase relationship governed by the ratios of the coupling impedance. Finally, the developed theoretical formulations have been shown to explain experimentally measured waveforms of such pairwise coupled relaxation Oscillators.
Abhinav Parihar - One of the best experts on this subject based on the ideXlab platform.
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synchronized charge oscillations in correlated electron systems
Scientific Reports, 2015Co-Authors: Nikhil Shukla, Abhinav Parihar, Eugene Freeman, Hanjong Paik, Greg Stone, Vijaykrishnan Narayanan, Venkatraman Gopalan, Roman Engelherbert, D G Schlom, Arijit RaychowdhuryAbstract:Strongly correlated phases exhibit collective carrier dynamics that if properly harnessed can enable novel functionalities and applications. In this article, we investigate the phenomenon of electrical oscillations in a prototypical MIT system, vanadium dioxide (VO2). We show that the key to such Oscillatory behaviour is the ability to induce and stabilize a non-hysteretic and spontaneously reversible phase transition using a negative feedback mechanism. Further, we investigate the synchronization and coupling dynamics of such VO2 based relaxation Oscillators and show, via experiment and simulation, that this coupled Oscillator system exhibits rich non-linear dynamics including charge oscillations that are synchronized in both frequency and phase. Our approach of harnessing a non-hysteretic reversible phase transition region is applicable to other correlated systems exhibiting metal-insulator transitions and can be a potential candidate for Oscillator based non-Boolean computing.
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synchronization of pairwise coupled identical relaxation Oscillators based on metal insulator phase transition devices a model study
Journal of Applied Physics, 2015Co-Authors: Abhinav Parihar, Nikhil Shukla, Suman Datta, Arijit RaychowdhuryAbstract:Computing with networks of synchronous Oscillators has attracted wide-spread attention as novel materials and device topologies have enabled realization of compact, scalable and low-power coupled Oscillatory systems. Of particular interest are compact and low-power relaxation Oscillators that have been recently demonstrated using MIT (metal-insulator-transition) devices using properties of correlated oxides. Further the computational capability of pairwise coupled relaxation Oscillators has also been shown to outperform traditional Boolean digital logic circuits. This paper presents an analysis of the dynamics and synchronization of a system of two such identical coupled relaxation Oscillators implemented with MIT devices. We focus on two implementations of the Oscillator: (a) a D-D configuration where complementary MIT devices (D) are connected in series to provide oscillations and (b) a D-R configuration where it is composed of a resistor (R) in series with a voltage-triggered state changing MIT device ...
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synchronization of pairwise coupled identical relaxation Oscillators based on metal insulator phase transition devices a model study
arXiv: Chaotic Dynamics, 2014Co-Authors: Abhinav Parihar, Nikhil Shukla, Suman Datta, Arijit RaychowdhuryAbstract:Computing with networks of synchronous Oscillators has attracted wide-spread attention as novel materials and device topologies have enabled realization of compact, scalable and low-power coupled Oscillatory systems. Of particular interest are compact and low-power relaxation Oscillators that have been recently demonstrated using MIT (metal- insulator-transition) devices using properties of correlated oxides. This paper presents an analysis of the dynamics and synchronization of a system of two such identical coupled relaxation Oscillators implemented with MIT devices. We focus on two implementations of the Oscillator: (a) a D-D configuration where complementary MIT devices (D) are connected in series to provide oscillations and (b) a D-R configuration where it is composed of a resistor (R) in series with a voltage-triggered state changing MIT device (D). The MIT device acts like a hysteresis resistor with different resistances in the two different states. The synchronization dynamics of such a system has been analyzed with purely charge based coupling using a resistive (Rc) and a capacitive (Cc) element in parallel. It is shown that in a D-D configuration symmetric, identical and capacitively coupled relaxation Oscillator system synchronizes to an anti-phase locking state, whereas when coupled resistively the system locks in phase. Further, we demonstrate that for certain range of values of Rc and Cc, a bistable system is possible which can have potential applications in associative computing. In D-R configuration, we demonstrate the existence of rich dynamics including non-monotonic flows and complex phase relationship governed by the ratios of the coupling impedance. Finally, the developed theoretical formulations have been shown to explain experimentally measured waveforms of such pairwise coupled relaxation Oscillators.
Nikhil Shukla - One of the best experts on this subject based on the ideXlab platform.
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synchronized charge oscillations in correlated electron systems
Scientific Reports, 2015Co-Authors: Nikhil Shukla, Abhinav Parihar, Eugene Freeman, Hanjong Paik, Greg Stone, Vijaykrishnan Narayanan, Venkatraman Gopalan, Roman Engelherbert, D G Schlom, Arijit RaychowdhuryAbstract:Strongly correlated phases exhibit collective carrier dynamics that if properly harnessed can enable novel functionalities and applications. In this article, we investigate the phenomenon of electrical oscillations in a prototypical MIT system, vanadium dioxide (VO2). We show that the key to such Oscillatory behaviour is the ability to induce and stabilize a non-hysteretic and spontaneously reversible phase transition using a negative feedback mechanism. Further, we investigate the synchronization and coupling dynamics of such VO2 based relaxation Oscillators and show, via experiment and simulation, that this coupled Oscillator system exhibits rich non-linear dynamics including charge oscillations that are synchronized in both frequency and phase. Our approach of harnessing a non-hysteretic reversible phase transition region is applicable to other correlated systems exhibiting metal-insulator transitions and can be a potential candidate for Oscillator based non-Boolean computing.
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synchronization of pairwise coupled identical relaxation Oscillators based on metal insulator phase transition devices a model study
Journal of Applied Physics, 2015Co-Authors: Abhinav Parihar, Nikhil Shukla, Suman Datta, Arijit RaychowdhuryAbstract:Computing with networks of synchronous Oscillators has attracted wide-spread attention as novel materials and device topologies have enabled realization of compact, scalable and low-power coupled Oscillatory systems. Of particular interest are compact and low-power relaxation Oscillators that have been recently demonstrated using MIT (metal-insulator-transition) devices using properties of correlated oxides. Further the computational capability of pairwise coupled relaxation Oscillators has also been shown to outperform traditional Boolean digital logic circuits. This paper presents an analysis of the dynamics and synchronization of a system of two such identical coupled relaxation Oscillators implemented with MIT devices. We focus on two implementations of the Oscillator: (a) a D-D configuration where complementary MIT devices (D) are connected in series to provide oscillations and (b) a D-R configuration where it is composed of a resistor (R) in series with a voltage-triggered state changing MIT device ...
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synchronization of pairwise coupled identical relaxation Oscillators based on metal insulator phase transition devices a model study
arXiv: Chaotic Dynamics, 2014Co-Authors: Abhinav Parihar, Nikhil Shukla, Suman Datta, Arijit RaychowdhuryAbstract:Computing with networks of synchronous Oscillators has attracted wide-spread attention as novel materials and device topologies have enabled realization of compact, scalable and low-power coupled Oscillatory systems. Of particular interest are compact and low-power relaxation Oscillators that have been recently demonstrated using MIT (metal- insulator-transition) devices using properties of correlated oxides. This paper presents an analysis of the dynamics and synchronization of a system of two such identical coupled relaxation Oscillators implemented with MIT devices. We focus on two implementations of the Oscillator: (a) a D-D configuration where complementary MIT devices (D) are connected in series to provide oscillations and (b) a D-R configuration where it is composed of a resistor (R) in series with a voltage-triggered state changing MIT device (D). The MIT device acts like a hysteresis resistor with different resistances in the two different states. The synchronization dynamics of such a system has been analyzed with purely charge based coupling using a resistive (Rc) and a capacitive (Cc) element in parallel. It is shown that in a D-D configuration symmetric, identical and capacitively coupled relaxation Oscillator system synchronizes to an anti-phase locking state, whereas when coupled resistively the system locks in phase. Further, we demonstrate that for certain range of values of Rc and Cc, a bistable system is possible which can have potential applications in associative computing. In D-R configuration, we demonstrate the existence of rich dynamics including non-monotonic flows and complex phase relationship governed by the ratios of the coupling impedance. Finally, the developed theoretical formulations have been shown to explain experimentally measured waveforms of such pairwise coupled relaxation Oscillators.
Nicolas E Buchler - One of the best experts on this subject based on the ideXlab platform.
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role of dna binding sites and slow unbinding kinetics in titration based Oscillators
Physical Review E, 2015Co-Authors: Sargis Karapetyan, Nicolas E BuchlerAbstract:Genetic Oscillators, such as circadian clocks, are constantly perturbed by molecular noise arising from the small number of molecules involved in gene regulation. One of the strongest sources of stochasticity is the binary noise that arises from the binding of a regulatory protein to a promoter in the chromosomal DNA. In this study, we focus on two minimal Oscillators based on activator titration and repressor titration to understand the key parameters that are important for oscillations and for overcoming binary noise. We show that the rate of unbinding from the DNA, despite traditionally being considered a fast parameter, needs to be slow to broaden the space of Oscillatory solutions. The addition of multiple, independent DNA binding sites further expands the Oscillatory parameter space for the repressor-titration Oscillator and lengthens the period of both Oscillators. This effect is a combination of increased effective delay of the unbinding kinetics due to multiple binding sites and increased promoter ultrasensitivity that is specific for repression. We then use stochastic simulation to show that multiple binding sites increase the coherence of oscillations by mitigating the binary noise. Slow values of DNA unbinding rate are also effective in alleviating molecular noise due to the increased distance from the bifurcation point. Our work demonstrates how the number of DNA binding sites and slow unbinding kinetics, which are often omitted in biophysical models of gene circuits, can have a significant impact on the temporal and stochastic dynamics of genetic Oscillators.
Julie Grollier - One of the best experts on this subject based on the ideXlab platform.
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self injection locking of a vortex spin torque Oscillator by delayed feedback
Scientific Reports, 2016Co-Authors: S Tsunegi, Eva Grimaldi, Romain Lebrun, Hitoshi Kubota, A S Jenkins, Kay Yakushiji, Akio Fukushima, Paolo Bortolotti, Julie GrollierAbstract:The self-synchronization of spin torque Oscillators is investigated experimentally by re-injecting its radiofrequency (rf) current after a certain delay time. We demonstrate that the integrated power and spectral linewidth are improved for optimal delays. Moreover by varying the phase difference between the emitted power and the re-injected one, we find a clear Oscillatory dependence on the phase difference with a 2π periodicity of the frequency of the Oscillator as well as its power and linewidth. Such periodical behavior within the self-injection regime is well described by the general model of nonlinear auto-Oscillators including not only a delayed rf current but also all spin torque forces responsible for the self-synchronization. Our results reveal new approaches for controlling the non-autonomous dynamics of spin torque Oscillators, a key issue for rf spintronics applications as well as for the development of neuro-inspired spin-torque Oscillators based devices.
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self injection locking of a vortex spin torque Oscillator by delayed feedback
arXiv: Mesoscale and Nanoscale Physics, 2015Co-Authors: S Tsunegi, Eva Grimaldi, Romain Lebrun, Hitoshi Kubota, A S Jenkins, Kay Yakushiji, Akio Fukushima, Paolo Bortolotti, Julie GrollierAbstract:The self-synchronization of spin torque Oscillators is investigated experimentally by re-injecting its radiofrequency (rf) current after a certain delay time. We demonstrate that the emission power and the spectral linewidth are improved for optimal delay times. Moreover by varying the phase difference between the emitted power and the re-injected one, we find a clear Oscillatory dependence with a 2\pi\ periodicity of the frequency of the Oscillator as well as its power and linewidth. Such periodical behavior within the self-injection regime is well described by the general model of nonlinear auto-Oscillators including not only a delayed rf current but also all spin torque forces responsible for the self-synchronization. Our results reveal new approaches for controlling the non-autonomous dynamics of spin torque Oscillators, a key issue for rf spintronics applications as well as for the development of neuro-inspired spin-torque Oscillators based devices.
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synchronization of spin transfer Oscillators driven by stimulated microwave currents
Physical Review B, 2006Co-Authors: Julie Grollier, Vincent Cros, A FertAbstract:We have simulated the nonlinear dynamics of networks of spin-transfer Oscillators. The Oscillators are magnetically uncoupled but electrically connected in series. We use a modified Landau-Lifschitz-Gilbert equation to describe the motion of each Oscillator in the presence of the oscillations of all the others. We show that the Oscillators of the network can be locked not only in frequency but also in phase. The coupling is due to the microwave components of the current induced in each Oscillator by the oscillations in all the other Oscillators. Our results show how the emitted microwave power of spin-transfer Oscillators can be considerably enhanced by current-induced synchronization in an electrically connected network. We also discuss the possible application of our synchronization mechanism to the interpretation of the surprisingly narrow microwave spectrum in some experiments on a single isolated spin-transfer Oscillator.
