scholarly journals Steady-state entanglement by engineered quasi-local Markovian dissipation

2014 ◽  
Vol 14 (3&4) ◽  
pp. 265-294
Author(s):  
Francesco Ticozzi ◽  
Lorenza Viola
Keyword(s):  
Steady State ◽  
Previous Analysis ◽  
W States ◽  
Finite Dimensional ◽  
Markovian Dynamics ◽  
Control Schemes ◽  
Suitable Combination ◽  
Initial States ◽  
Cat States ◽  
Physical Locality

We characterize time-independent Markovian dynamics that drive a finite-dimensional multipartite quantum system into a target (pure) entangled steady state, subject to physical locality constraints. New control schemes are introduced in situations where the desired stabilization task {\em cannot} be attained solely based on quasi-local dissipative means, as considered in previous analysis. The new schemes either allow for Hamiltonian control or, if the latter is not an option, suitably restrict the set of admissible initial states. In both cases, we provide explicit algorithms for constructing a Markovian master equation that achieves the intended objective and show how this genuinely extends the manifold of stabilizable states. In particular, we present dissipative quasi-local control protocols for deterministically engineering multipartite GHZ ``cat'' states and W states on $n$ qubits. For GHZ states, we show that no scalable procedure exists for achieving stabilization from arbitrary initial states, whereas this is possible for a target W state by a suitable combination of a two-body Hamiltonian and dissipators. Interestingly, for both entanglement classes, we show that quasi-local stabilization may be {\em scalably} achieved conditional to initialization of the system in a large, appropriately chosen subspace.

Quantum universality by state distillationIndirect quantum control for finite-dimensional coupled systems

2010 ◽  
Vol 10 (1&2) ◽  
pp. 87-96
Author(s):  
J. Nie ◽  
H.C. Fu ◽  
X.X. Yi
Keyword(s):  
Quantum System ◽  
Quantum Control ◽  
Coherent Control ◽  
Coupled Systems ◽  
Preparation Technology ◽  
State Preparation ◽  
Finite Dimensional ◽  
State Dependent ◽  
Control Scheme ◽  
Initial States

We present a new analysis on the quantum control for a quantum system coupled to a quantum probe. This analysis is based on the coherent control for the quantum system and a hypothesis that the probe can be prepared in specified initial states. The results show that a quantum system can be manipulated by probe state-dependent coherent control. In this sense, the present analysis provides a new control scheme which combines the coherent control and state preparation technology.

Optimal Intervention Methods for Markovian Gene Regulatory Networks

2016 ◽  
pp. 161-208
Author(s):  
Mohammadmahdi Rezaei Yousefi
Keyword(s):  
Steady State ◽  
Regulatory Networks ◽  
External Control ◽  
Treatment Goals ◽  
State Behavior ◽  
Optimal Intervention ◽  
Markovian Dynamics ◽  
Gene Regulatory ◽  
Maximal Shift ◽  
Steady State Behavior

A central problem in translational medicine is to provide a framework for deriving and studying effective intervention methods to elicit desired steady-state behavior for a gene regulatory network of interest with Markovian dynamics. Heretofore, two rather different external control approaches have been taken. The first optimizes a subjectively defined cost function while modeling treatment constraints; therefore, desirable shift of the steady-state mass is a by-product. The second approach, on the other hand, focuses solely on the steady-state behavior of the network and provides the maximal shift achievable. Although both approaches are optimal with respect to their objectives, the choice of which to use depends on the treatment goals.

Asymptotic Impact Control of Hydraulic Actuators With Friction

2004 ◽  
Author(s):  
P. Sekhavat ◽  
N. Sepehri ◽  
Q. Wu
Keyword(s):  
Steady State ◽  
Nonlinear Control ◽  
Dry Friction ◽  
Position Control ◽  
Past Research ◽  
Hydraulic Actuator ◽  
Stick Slip ◽  
Hydraulic Actuators ◽  
Control Scheme ◽  
Control Schemes

The focus of this work is stabilization of hydraulic actuators during the transition from free motion to constraint motion and regulating the intermediate impacts that could drive the system unstable. In our past research, we introduced Lyapunov-based nonlinear control schemes capable of fulfilling the above goal by resting the implement on the surface of the environment before starting the sustained-contact motion. The hydraulic actuator’s stick-slip friction effect was, however, either not included in the analysis or not compensated by the control action. In this paper, the application of our previously introduced friction compensating position control scheme is extended to impact regulation of a hydraulic actuator. Theoretical solution and stability analyses as well as actual experiments prove that such control scheme is also effective for asymptotic impact control (with no position steady-state error) of hydraulic actuators in the presence of actuator’s dry friction.

ENTANGLEMENT DYNAMICS OF TWO QUBITS COUPLED TO SQUEEZED DISSIPATIVE ENVIRONMENTS

2010 ◽  
Vol 24 (26) ◽  
pp. 2635-2645
Author(s):  
CHUAN-JIA SHAN ◽  
TAO CHEN ◽  
JI-BING LIU ◽  
WEI-WEN CHENG ◽  
TANG-KUN LIU ◽  
...  
Keyword(s):  
Steady State ◽  
Sudden Death ◽  
Entangled States ◽  
Entanglement Sudden Death ◽  
Entanglement Dynamics ◽  
Initial Product ◽  
System Parameters ◽  
Initial States ◽  
Dissipative Environments ◽  
Degree Of Entanglement

By analytically solving the Lindblad form of the master equation, we investigate entanglement dynamics of two qubits coupled via the XY interaction, where each qubit is interacting with an independent reservoir with the squeezing parameters and squeezing angles. In the weak-squeezed reservoir, we show that the entanglement sudden death and entanglement sudden birth will happen for various entangled states. Some initial product states evolve into entangled ones, initially entangled states lose completely or partially their entanglement. The effects of varying the degree of entanglement of the initial states, the spin chain system parameters and different values of the degree of squeezing on the sudden death, revival and birth times are analyzed in detail. We also see that the steady state concurrence appears in the squeezed dissipative environments, which is affected by both the system parameters and the degree of squeezing.

scholarly journals THE STABILITY OF QUANTUM MARKOV FILTERS

2009 ◽  
Vol 12 (01) ◽  
pp. 153-172 ◽  
Author(s):  
RAMON VAN HANDEL
Keyword(s):  
Differential Equation ◽  
Stochastic Model ◽  
Stochastic Differential Equation ◽  
Initial State ◽  
Rank Condition ◽  
Quantum Stochastic Differential Equation ◽  
Absolutely Continuous ◽  
Finite Dimensional ◽  
Initial States ◽  
The Stability

When are quantum filters asymptotically independent of the initial state? We show that this is the case for absolutely continuous initial states when the quantum stochastic model satisfies an observability condition. When the initial system is finite dimensional, this condition can be verified explicitly in terms of a rank condition on the coefficients of the associated quantum stochastic differential equation.

Experimental Characterization of Nonlinear Dynamics Underlying the Cylindrical Grinding Process

2004 ◽  
Vol 126 (2) ◽  
pp. 341-344 ◽  
Author(s):  
Satish T. S. Bukkapatnam ◽  
Rajkumar Palanna
Keyword(s):  
Nonlinear Dynamics ◽  
Fractal Dimension ◽  
Steady State ◽  
Grinding Process ◽  
Experimental Characterization ◽  
Cylindrical Grinding ◽  
Designed Experiments ◽  
Finite Dimensional ◽  
Major Implication

This paper presents our characterization of dynamics underlying the cylindrical grinding of shafts using accelerometer signals gathered from a set of designed experiments. The results of our characterizations show that the dynamics, under steady state, evolves into a finite-dimensional, perhaps chaotic, attractor contaminated by noise, with fractal dimension values hovering between 3.1 and 3.8. The major implication of this finding is in the development of tractable models to control this industrially important shaft grinding process.

scholarly journals Dissipation-driven integrable fermionic systems: from graded Yangians to exact nonequilibrium steady states

2017 ◽  
Vol 3 (4) ◽  
Author(s):  
Enej Ilievski
Keyword(s):  
Steady State ◽  
Lattice Models ◽  
State Density ◽  
Nonequilibrium Steady States ◽  
Matrix Product ◽  
Finite Dimensional ◽  
Master Equation Approach ◽  
Boundary Dissipation ◽  
Higher Rank ◽  
Far From Equilibrium

Using the Lindblad master equation approach, we investigate the structure of steady-state solutions of open integrable quantum lattice models, driven far from equilibrium by incoherent particle reservoirs attached at the boundaries. We identify a class of boundary dissipation processes which permits to derive exact steady-state density matrices in the form of graded matrix-product operators. All the solutions factorize in terms of vacuum analogues of Baxter’s Q-operators which are realized in terms of non-unitary representations of certain finite dimensional subalgebras of graded Yangians. We present a unifying framework which allows to solve fermionic models and naturally incorporates higher-rank symmetries. This enables to explain underlying algebraic content behind most of the previously-found solutions.

scholarly journals Adaptive Control for Quadrotors with Uncertain and Faulty Actuators

2021 ◽  
Author(s):  
Qi Han ◽  
Xiangbin Liu ◽  
Zhitao Liu ◽  
Hongye Su
Keyword(s):  
Adaptive Control ◽  
Steady State ◽  
Fault Tolerant ◽  
Control Strategies ◽  
Adaptive Controllers ◽  
Immersion And Invariance ◽  
Control Schemes ◽  
Simulation And Experiment ◽  
Actuator System ◽  
Backstepping Controller

Abstract Two adaptive control strategies are presented in this paper for two types of quadrotors to cope with potential uncertainties and faults in the actuator system. The four actuators of the considered quadrotors are distinct and suffered from loss of effectiveness (LOE) as well. To accomandate unknown actuator parameters, a filter-based immersion and invariance (I&I) adaptive controllers are designed for attitude and altitude subsystems, respectively, and an integral backstepping controller is developed for the horizontal subsystem to achieve null steady-state error. Both simulation and experiment results are carried out to illustrate the effectiveness of trajectory tracking performance and fault-tolerant accomondation ability of the proposed control schemes.

Transient Behaviors of Multiple Memristor Circuits Based on Flux Charge Relationship

2014 ◽  
Vol 24 (02) ◽  
pp. 1430006 ◽  
Author(s):  
Ram Kaji Budhathoki ◽  
Maheshwar P. D. Sah ◽  
Changju Yang ◽  
Hyongsuk Kim ◽  
Leon Chua
Keyword(s):  
Steady State ◽  
Transient State ◽  
Input Voltage ◽  
Computation Method ◽  
Initial State ◽  
Transient Characteristics ◽  
Initial States ◽  
Charge Flux ◽  
Parallel Connections ◽  
Flux Charge

Memristor, a new electrical element, can have various configurations of multiple memristors, including serial and parallel connections like previous elements R, L and C. When input voltage/current is supplied to a circuit with multiple memristors, the composite behavior of the memristor circuit exhibits transient states before it enters a steady state. During the transient state period, the behavior is very complex and not predictable due to each memristor's different action depending upon its connection polarity and initial state. In this paper, the transient characteristics of a composite memristor are analyzed via the relationships of charge, flux and memristance of each memristor. Also, the behavior of an individual memristor is formulated mathematically and a general computation method of composite memristance for multiple-memristor circuits of diverse configurations is proposed. Various simulations have also been performed to verify the effectiveness of the proposed method for differently configured memristor circuits, in terms of polarities and initial states.

scholarly journals On Howland time-independent formulation of CP-divisible quantum evolutions

2020 ◽  
Vol 32 (07) ◽  
pp. 2050021
Author(s):  
Krzysztof Szczygielski ◽  
Robert Alicki
Keyword(s):  
Open Quantum Systems ◽  
Standard Form ◽  
Quantum Systems ◽  
Matrix Space ◽  
Product Representation ◽  
Completely Positive ◽  
Finite Dimensional ◽  
Markovian Dynamics ◽  
Bochner Space ◽  
Densely Defined

We extend Howland time-independent formalism to the case of completely positive and trace preserving dynamics of finite-dimensional open quantum systems governed by periodic, time-dependent Lindbladian in Weak Coupling Limit, expanding our result from previous papers. We propose the Bochner space of periodic, square integrable matrix-valued functions, as well as its tensor product representation, as the generalized space of states within the time-independent formalism. We examine some densely defined operators on this space, together with their Fourier-like expansions and address some problems related to their convergence by employing general results on Banach space-valued Fourier series, such as the generalized Carleson–Hunt theorem. We formulate Markovian dynamics in the generalized space of states by constructing appropriate time-independent Lindbladian in standard (Lindblad–Gorini–Kossakowski–Sudarshan) form, as well as one-parameter semigroup of bounded evolution maps. We show their similarity with Markovian generators and dynamical maps defined on matrix space, i.e. the generator still possesses a standard form (extended by closed perturbation) and the resulting semigroup is also completely positive, trace preserving and a contraction.

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