6 results on '"Luchnikov, I. A."'
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2. Super-relaxation of space–time-quantized ensemble of energy loads to curtail their synchronization after demand response perturbation.
- Author
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Luchnikov, I., Métivier, D., Ouerdane, H., and Chertkov, M.
- Subjects
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SYNCHRONIZATION , *STOCHASTIC matrices , *ENERGY consumption , *ELECTRIC power distribution grids , *INFORMATION resources management - Abstract
Ensembles of thermostatically controlled loads (TCL) provide a significant demand response reserve for the system operator to balance power grids. However, this also results in the parasitic synchronization of individual devices within the ensemble leading to long post-demand-response oscillations in the integrated energy consumption of the ensemble. The synchronization is eventually destructed by fluctuations, thus leading to the (pre-demand response) steady state; however, this natural desynchronization, or relaxation to a statistically steady state, is too long. A resolution of this problem consists in measuring the ensemble's instantaneous consumption and using it as a feedback to stochastic switching of the ensemble's devices between on- and off-states. A simplified continuous-time model showed that carefully tuned nonlinear feedback results in a fast (super-) relaxation of the ensemble energy consumption. Since both state information and control signals are discrete, the actual TCL devices operation is space–time quantized, and this must be considered for realistic TCL ensemble modeling. Here, assuming that states are characterized by indoor temperature (quantifying comfort) and air conditioner regime (on, off), we construct a discrete model based on the probabilistic description of state transitions. We demonstrate that super-relaxation holds in such a more realistic setting, and that while it is stable against randomness in the stochastic matrix of the quantized model, it remains sensitive to the time discretization scheme. Aiming to achieve a balance between super-relaxation and customer's comfort, we analyze the dependence of super-relaxation on details of the space–time quantization, and provide a simple analytical criterion to avoid undesirable oscillations in consumption. • Super-relaxation of ensemble of energy loads is beneficial for demand response. • Criteria for ensemble consumption dynamics instability are established. • A simple analytical criterion to avoid undesirable oscillations in consumption is given. • The proposed mean-field approach may be extended to integrated energy systems. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
3. Machine Learning Non-Markovian Quantum Dynamics.
- Author
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Luchnikov, I. A., Vintskevich, S. V., Grigoriev, D. A., and Filippov, S. N.
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QUANTUM theory , *MACHINE learning , *MAXIMUM likelihood statistics , *STATISTICS , *SYSTEM dynamics - Abstract
Machine learning methods have proved to be useful for the recognition of patterns in statistical data. The measurement outcomes are intrinsically random in quantum physics, however, they do have a pattern when the measurements are performed successively on an open quantum system. This pattern is due to the system-environment interaction and contains information about the relaxation rates as well as non-Markovian memory effects. Here we develop a method to extract the information about the unknown environment from a series of projective single-shot measurements on the system (without resorting to the process tomography). The method is based on embedding the non-Markovian system dynamics into a Markovian dynamics of the system and the effective reservoir of finite dimension. The generator of Markovian embedding is learned by the maximum likelihood estimation. We verify the method by comparing its prediction with an exactly solvable non-Markovian dynamics. The developed algorithm to learn unknown quantum environments enables one to efficiently control and manipulate quantum systems. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
4. Simulation Complexity of Open Quantum Dynamics: Connection with Tensor Networks.
- Author
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Luchnikov, I. A., Vintskevich, S. V., Ouerdane, H., and Filippov, S. N.
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QUANTUM theory , *DEGREES of freedom , *QUANTUM mechanics , *MATRIX multiplications , *HILBERT space , *QUANTUM thermodynamics - Abstract
The difficulty to simulate the dynamics of open quantum systems resides in their coupling to many-body reservoirs with exponentially large Hilbert space. Applying a tensor network approach in the time domain, we demonstrate that effective small reservoirs can be defined and used for modeling open quantum dynamics. The key element of our technique is the timeline reservoir network (TRN), which contains all the information on the reservoir's characteristics, in particular, the memory effects timescale. The TRN has a one-dimensional tensor network structure, which can be effectively approximated in full analogy with the matrix product approximation of spin-chain states. We derive the sufficient bond dimension in the approximated TRN with a reduced set of physical parameters: coupling strength, reservoir correlation time, minimal timescale, and the system's number of degrees of freedom interacting with the environment. The bond dimension can be viewed as a measure of the open dynamics complexity. Simulation is based on the semigroup dynamics of the system and effective reservoir of finite dimension. We provide an illustrative example showing the scope for new numerical and machine learning-based methods for open quantum systems. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
5. Quantum evolution in the stroboscopic limit of repeated measurements.
- Author
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Luchnikov, I. A. and Filippov, S. N.
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QUANTUM theory , *DYNAMICS , *DECOHERENCE (Quantum mechanics) - Abstract
We consider a quantum system dynamics caused by successive selective and nonselective measurements of the probe coupled to the system. For the finite measurement rate τ-1 and the system-probe interaction strength γ we derive analytical evolution equations in the stroboscopic limit τ→0 and γ2τ=const, which can be considered as a deviation from the Zeno subspace dynamics on a longer time scale T∼(γ2τ)-1≫γ-1. Nonlinear quantum dynamics is analyzed for selective stroboscopic projective measurements of an arbitrary rank. Nonselective measurements are shown to induce the semigroup dynamics of the system-probe aggregate. Both nonlinear and decoherent effects become significant at the time scale T∼(γ2τ)-1, which is illustrated by a number of examples. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
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6. Light-assisted collisions in ultracold Tm atoms.
- Author
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Cojocaru, I. S., Pyatchenkov, S. V., Snigirev, S. A., Luchnikov, I. A., Kalganova, E. S., Vishnyakova, G. A., Kublikova, D. N., Bushmakin, V. S., Davletov, E. T., Tsyganok, V. V., Belyaeva, O. V., Khoroshilov, A., Sorokin, V. N., Sukachev, D. D., and Akimov, A. V.
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COLLISIONS (Nuclear physics) , *MAGNETOOPTICAL trapping , *BRANCHING ratios - Abstract
We studied light-assisted collisions of Tm atoms in a magneto-optical trap (MOT), working on a weak cooling transition at 530.7 nm [4f13(²Fo)6s²,J=7/2,F=4 to 4f12(³H6)5d5/26s²,J=9/2,F=5]. We observed a strong influence from radiation trapping and light-assisted collisions on the dynamics of this trap. We carefully separated these two contributions and measured the binary loss rate constant at different laser powers and detuning frequencies near the cooling transition. Analyzing losses from the MOT, we found the light-assisted inelastic binary loss rate constant to reach values of up to β=10-9cm³/s and gave the upper bound on a branching ratio k<0.8×10-6 for the 530.7 nm transition. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
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