arXiv subjects

Alireza Nourmandipour

Publications and source records attributed to Alireza Nourmandipour.

At least 19 recordsLinked to original sources

arXiv2026

Emergent Dissipation from Fluctuating Quantum-Network Topology

We investigate how dissipation can emerge in a quantum network from temporal fluctuations of the interaction topology. For a network whose graph is redrawn at short time intervals, the averaged dynamics yields a Markovian master equation: the mean network fixes the coherent part and the covariance fixes the dissipative structure. The covariance eigenvalues set the noise strengths, while its eigenvectors determine the collective operators on which those strengths act. Two ensembles with identical mean adjacency and covariance spectra but different eigenvectors produce distinct dynamics despite identical purity. A physically realizable model yields an analytically predicted dissipative gap, giving quasi-protected dynamics. These results establish fluctuating connectivity as a resource for engineering quantum dissipation and protection.

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arXiv2026

Collective-dissipation-controlled thermal rectification and entropy production in a three-terminal three-qubit XXZ spin chain

We investigate thermal rectification and its thermodynamic cost in a three-qubit XXZ spin chain coupled to three thermal reservoirs: two local baths attached to the boundary qubits and a collective bath jointly coupled to the middle and right qubits. This asymmetric dissipative architecture allows the collective environment to actively reshape energy transport. We show that the heat current carried by the collective bath changes sign as its temperature is varied, and that the spin-chain anisotropy provides an effective internal control parameter for suppressing the boundary heat currents. These features yield thermal rectification coefficients of about $3.36\%$ at maximum bias and up to $20.1\%$ in the strongly anisotropic regime, although the latter comes at the cost of severely reduced heat currents. Beyond rectification, we evaluate the steady-state entropy production rate and identify a low-irreversibility operating window near the collective-current reversal, whereas increasing the local boundary couplings monotonically raises the thermodynamic cost. Our results establish collective dissipation as a tunable control mechanism for quantum heat transport and uncover a nontrivial trade-off among rectification, heat-current magnitude, and irreversible losses.

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arXiv2026

Kerr Induced Control of Synchronization and Quantum State Recovery in a Driven van der Pol Oscillator

We investigate how Kerr nonlinearity modifies quantum synchronization in a squeezed quantum van der Pol oscillator. We show that the Kerr interaction produces an amplitude-dependent frequency shift that drives a saddle-node bifurcation, transforming the classical phase-space structure from bistable to monostable dynamics. In the quantum regime, this transition manifests as systematic frequency pulling and spectral broadening, while the steady-state Wigner function reveals a continuous correspondence between the quantum state and the semiclassical attractor despite finite quantum fluctuations. By constructing global synchronization phase diagrams in the squeezing--Kerr parameter space, we uncover a remarkably linear dependence of the critical squeezing strength required to maintain phase locking on the Kerr nonlinearity. We further demonstrate that the synchronization boundary does not coincide with the crossover between super- and sub-Poissonian photon statistics, showing that synchronization and photon-number statistics characterize distinct aspects of the quantum steady state. These results provide quantitative design principles for controlling quantum synchronization through Kerr nonlinearity, with potential relevance to trapped-ion, superconducting-circuit, and optomechanical platforms.

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arXiv2025

Synergistic Effects of Detuning and Auxiliary Qubits on Quantum Synchronization

We investigate how detuning and auxiliary qubits collaboratively enhance quantum synchronization in a dissipative multi-qubit system that is coupled to a structured reservoir. Our findings indicate that while detuning is ineffective in Markovian environments, it emerges as a powerful control parameter in the non-Markovian regime, where environmental memory facilitates long-lived phase coherence. It is shown that adding more auxiliary qubits amplifies this effect by strengthening the collective coupling and enhancing memory, resulting in robust phase locking within the system. Analysis using the Husimi Q-function, synchronization measures, and Arnold tongue structures reveals a detuning-induced enhancement of phase locking, which significantly improves stability compared to the resonance case. These results establish a cooperative control strategy where detuning actively engineers phases, while auxiliary qubits provide the necessary memory for sustained synchronization.

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arXiv2025

Investigating the Impact of Qubit Velocity on Quantum Synchronization Dynamics

We investigate the quantum synchronization dynamics of a moving qubit interacting with a dissipative cavity environment, using the Husimi $Q$-function to analyze its phase space evolution. Unlike conventional synchronization between separate subsystems, we focus on self-synchronization phenomena, where the qubit's phase dynamics exhibit locking to its initial phase distribution. We explore the effects of varying qubit velocity and system detuning across weak and strong coupling regimes. In the weak coupling regime, the system rapidly decoheres with minimal phase preference. In contrast, strong coupling leads to the emergence and persistence of a distinct phase peak, indicating phase locking and enhanced synchronization. These results offer insight into how motion and detuning can regulate coherence and phase stability in open quantum systems. Our approach aligns with recent studies that generalize synchronization concepts to single quantum systems.

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arXiv2024

Enhancing Quantum Synchronization in a driven qubit system coupled to a structured environment

In this paper, we delve into the issue of Quantum Synchronization in a driven two-level (qubit) system situated within a structured environment. Our findings have practical implications as we discover that adding a time-dependent periodic modulation to the transition frequency of the qubit can significantly enhance quantum synchronization. We first discovered the phase preference and, consequently, the phase locking conditions in our system using the Husimi Q-function. It is revealed that combining frequency modulation and non-Markovian effects enables us to achieve a stable phase-locking for the system. We show that tuning the amplitude-tofrequency ratio of the modulation process on the zeros of the zeroth-order Bessel function led to phase locking and, thus, surprisingly enhances quantum synchronization in the system. These results provide new insights into efficiently understanding phase dynamics in quantum environments.

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arXiv2023

Routing a quantum state in a bio-inspired network

We consider a spin network resembling an $α$-helix structure and study quantum information transfer over this bio-inspired network. The model we use is the Davydov model in its elementary version without a phononic environment. We investigate analytically and numerically the perfect state transfer (PST) in such a network which provides an upper bound on the probability of quantum states transfer from one node to another. We study PST for different boundary conditions on the network and show it is reachable between certain nodes and with suitable spin-spin couplings.

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arXiv2021

Entanglement Protection of Classically Driven Qubits in a Lossy Cavity

Quantum technologies able to manipulating single quantum systems, are presently developing. Among the dowries of the quantum realm, entanglement is one of the basic resources for the novel quantum revolution. Within this context, one is faced with the problem of protecting the entanglement when a system state is manipulated. In this paper, we investigate the effect of the classical driving field on the generation entanglement between two qubits interacting with a bosonic environment. We discuss the effect of the classical field on the generation of entanglement between two (different) qubits and the conditions under which it has a constructive role in protecting the initial-state entanglement from decay induced by its environment. In particular, in the case of similar qubits, we locate a stationary sub-space of the system Hilbert space, characterized by states non depending on the environment properties as well as on the classical driving-field. Thus, we are able to determine the conditions to achieve maximally entangled stationary states after a transient interaction with the environment. We show that, overall, the classical driving field has a constructive role for the entanglement protection in the strong coupling regime. Also, we illustrate that a factorable initial-state can be driven in an entangled state and, even, in an entangled steady-state after the interaction with the environment.

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arXiv2020

Enforcing dissipative entanglement by feedback

We study the possibility of enhancing the stationary entanglement achievable with two-qubit dissipating into a common environment by means of feedback. We contrast the effect of Markovian with Bayesian feedback and show that, depending on the initial state, the performance of the latter are from 16% to 33% superior.

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arXiv2019

Qubit Movement-Assisted Entanglement Swapping

In this paper, we propose a scheme to generate entanglement between two distant qubits (two-level atom) which are separately trapped in their own (in general) non-Markovian dissipative cavities by utilizing entangling swapping. We consider the case in which the qubits can move along their cavity axes rather than a static state of motion. We first examine the role of movement of the qubit by studying the entropy evolution for each subsystem. We calculate the average entropy over the initial states of the qubit. Then by performing a Bell state measurement on the fields leaving the cavities, we swap the entanglement between qubit-field in each cavity into qubit-qubit and field-field subsystems. We use the entangling power to measure the average amount of swapped entanglement over all possible pure initial states. Our results are presented in two weak and strong coupling regimes. Our results illustrate the positive role of the movement of the qubits on the swapped entanglement. It is revealed that by considering certain conditions for the initial state of qubits, it is possible to achieve a maximally long-leaving stationary entanglement (Bell state) which is entirely independent of the environmental variables as well as the velocity of qubits. This happens when the two qubits have the same velocities.

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arXiv2019

The effect of classical driving field on the spectrum of a qubit and entanglement swapping inside dissipative cavities

In this paper, we study the effect of classical driving field on the spontaneous emission spectrum of a qubit embedded in a dissipative cavity. Furthermore, we monitor the entanglement dynamics of the driven qubit with its radiative decay under the action of the classical field. Afterwards, we carry out an investigation on the possibility of entanglement swapping between two such distinct driven qubits. The swapping will be feasible with the aid of a Bell state measurement performing on the photons leaving the cavities. It is demonstrated that the classical driving field has a beneficial effect on the prolonging of the swapped entanglement.

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arXiv2019

Entanglement dynamics of an arbitrary number of moving qubits in a common environment

In this paper we provide an analytical investigation of the entanglement dynamics of moving qubits dissipating into a common and (in general) non-Markovian environment for both weak and strong coupling regimes. We first consider the case of two moving qubits in a common environment and then generalize it to an arbitrary number of moving qubits. We show that for an initially entangled state, the environment washes out the initial entanglement after a finite interval of time. We also show that the movement of the qubits can play a constructive role in protecting of the initial entanglement. In this case, we observe a Zeno-like effect due to the velocity of the qubits. On the other hand, by limiting the number of qubits initially in a superposition of single excitation, a stationary entanglement can be achieved between the qubits initially in the excited and ground states. Surprisingly, we illustrate that when the velocity of all qubits are the same, the stationary state of the qubits does not depend on this velocity as well as the environmental properties. This allows us to determine the stationary distribution of the entanglement versus the total number of qubits in the system.

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arXiv2017

Dissipative entanglement swapping in the presence of detuning and Kerr medium: Bell state measurement method

In this paper, we investigate the possibility of the entanglement swapping between two independent nonperfect cavities consisting of an atom with finite lifetime of atomic levels (as two independent sources of dissipation) which interacts with a quantized electromagnetic field in the presence of detuning and Kerr medium. In fact, there is no direct interaction between the two atoms, therefore, no entanglement exists between them. We use the Bell state measurement performing on the photons leaving the cavities to swap the entanglement stored between the atom-fields in each cavity into atom-atom. Our motivation is arisen from the fact that two-qubit entangled states are of enough interest for quantum information science and technologies. We discuss the effect of initial state of the system, detuning parameter, the Kerr medium and the two dissipation sources on the swapped entanglement to atom-atom. We interestingly find that when the atomic decay rates and photonic leakages from the cavities are equal, our system behaves as an ideal system with no dissipation. Our results show that it is possible to create a long-living atom-atom maximally entangled state in the presence of Kerr effect and dissipation; we determine these conditions in detail and also establish the final atom-atom Bell state.

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arXiv2017

Universal feedback control of two-qubit entanglement

We consider two-qubit undergoing local dissipation and subject to local driving. We then determine the optimal Markovian feedback action to preserve initial entanglement as well as to create stationary entanglement with the help of an XY interaction Hamiltonian. Such feedback actions are worked out in a way not depending on the initial two-qubit state, whence called universal.

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arXiv2016

Entanglement Swapping Between Dissipative Systems

In this paper, we investigate the possibility of entanglement swapping between two distinct qubits coupled to their own (in general) non-Markovian environments. This is done via Bell state measurement performing on the photons leaving the dissipative cavities. In the continuation, we introduce the concept of entangling power to measure the average of swapped entanglement over all possible pure initial states. Then, we present our results in two strong and weak coupling regimes and discuss the role of detuning parameter in each regime on the amount of swapped entanglement. We also determine the conditions in which the maximum amount of entanglement can be swapped between two qubits. It is revealed that despite of the presence of dissipation, it is possible to create long-living stationary entanglement between two qubits.

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arXiv2016

Quantum Zeno and Anti-Zeno Effects on the Entanglement Dynamics of Qubits Dissipating into a Common and non-Markovian Environment

We investigate the quantum Zeno and anti-Zeno effects on pairwise entanglement dynamics of a collective of non-interacting qubits which have been initially prepared in a Werner state and are off-resonantly coupled to a common and non-Markovian environment. We obtain the analytical expression of the concurrence in the absence and presence of the non-selective measurements. In particular, we express our results in the strong and weak coupling regimes and examine the role of the system size, and the effect of the detuning from the cavity field frequency on the temporal behaviour of the pairwise entanglement. We show that, the detuning parameter has a positive role in the protection of entanglement in the absence of the measurement for weak coupling regime. We find that for the values of detuning parameter less than the cavity damping rate, the quantum Zeno effect is always dominant, while for the values greater than the cavity damping rate, both Zeno and anti-Zeno effects can occur, depending on the measurement intervals. We also find that the anti-Zeno effect can occur in the pairwise entanglement dynamics in the absence and presence of the detuning in the strong coupling regime.

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arXiv2016

Dynamics and Protecting of Entanglement in Two-Level Systems Interacting with a Dissipative Cavity: The Gardiner-Collett Approach

In this paper, we study the exact entanglement dynamics of two two-level atoms in a dissipative cavity. We use the Gardiner-Collett Hamiltonian to model the dissipative cavity, in which, we assume that the two atoms resonantly interact with the cavity field and the cavity field itself interacts with the surrounding medium. Then, with the help of the Fano's technique, we show that, this system can be regarded as two atoms interacting with a heat bath. In such a case, we find that, there exists a decoherence-free state that does not evolve in time. At this time, there exists a so-called super-radiant state which decays in time due to dissipation. At last, we use the quantum Zeno effect to preserve the entanglement which already has been stored in the system.

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arXiv2016

Optimal feedback control of two-qubit entanglement in dissipative environments

We study the correction of errors intervening in two-qubit dissipating into their own environments. This is done by resorting to local feedback actions with the aim of preserving as much as possible the initial amount of entanglement. Optimal control is found by first gaining insights from the subsystem purity and then by numerical analysis on the concurrence. This is tantamount to a double optimization, on the actuation and on the measurement processes. Repeated feedback action is also investigated, thus paving the way for a continuous time formulation and solution of the problem.

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