arXiv:2205.05971

Controlling the uncontrollable: Quantum control of open system dynamics

Shimshon Kallush, Roie Dann, Ronnie Kosloff

Published May 12, 2022• 2 citations

Abstract

Control of open quantum systems is an essential ingredient to the realization of contemporary quantum science and technology. We demonstrate such control by employing a thermodynamically consistent framework, taking into account the fact that the drive can modify the interaction with environment. Such an effect is incorporated within the dynamical equation, leading to control dependent dissipation, this relation serves as the key element for open system control. Thermodynamics of the control process is reflected by a unidirectional flow of energy to the environment resulting in large entropy production. The control paradigm is displayed by analyzing entropy changing state to state transformations, such as heating and cooling. In addition, the generation of quantum gates under dissipative conditions is demonstrated for both non-unitary reset maps with complete memory loss and a universal set of single and double qubit unitary gates.

DOI: 10.48550/arxiv.2205.05971

Related papers

Controlling the uncontrollable: Quantum control of open-system dynamics

Shimshon Kallush, Roie Dann, Ronnie Kosloff

Control of open quantum systems is essential for the realization of contemporary quantum science and technology. We demonstrate such control using a thermodynamically consistent framework, taking into account the fact that the drive can modify the system's interaction with the environment. Such an effect is incorporated within the dynamical equation, leading to control-dependent dissipation. This relation serves as the key element for open-system control. The control paradigm is displayed by analyzing entropy-changing state-to-state transformations, such as heating and cooling. The difficult task of controlling quantum gates is achieved for nonunitary reset maps with complete memory loss. In addition, we identify a mechanism for controlling unitary gates by actively removing entropy from the system to the environment. We demonstrate a universal set of single- and double-qubit unitary gates under dissipation.

Science AdvancesNov 2, 202230 citations

Controlling the uncontrollable: Quantum control of open system dynamics

Shimshon Kallush, Roie Dann, Ronnie Kosloff

Quantum control of an open system is demonstrated employing a thermodynamically consistent master equation. In this framework, the open system dynamics depend on the control protocol due to the dressing of the system by the drive. This interrelation serves as the key element for control. The influence of the external drive is incorporated within the dynamical equation, enabling an indirect control of the dissipation. The control paradigm is displayed by analyzing entropy changing state to state transformations, heating and cooling N-level systems. Following, we study the generation of quantum non-unitary maps via coherent control. These include both reset maps with complete memory loss and single-qubit unitary maps under dissipative conditions.

arXiv:2107.11767Jul 25, 20211 citation

Quantum thermo-dynamical construction for driven open quantum systems

Roie Dann, Ronnie Kosloff

Quantum dynamics of driven open systems should be compatible with both quantum mechanic and thermodynamic principles. By formulating the thermodynamic principles in terms of a set of postulates we obtain a thermodynamically consistent master equation. Following an axiomatic approach, we base the analysis on an autonomous description, incorporating the drive as a large transient control quantum system. In the appropriate physical limit, we derive the semi-classical description, where the control is incorporated as a time-dependent term in the system Hamiltonian. The transition to the semi-classical description reflects the conservation of global coherence and highlights the crucial role of coherence in the initial control state. We demonstrate the theory by analyzing a qubit controlled by a single bosonic mode in a coherent state.

arXiv:2012.07979QuantumNov 25, 202126 citations

Controlling open quantum systems

Benjamin Dive

All physical quantum systems are in contact with the external world which is inevitably a source of noise. It is therefore necessary to take into account this dissipation when designing controls that accomplish useful tasks in quantum information processing. This thesis is on that overlap of open quantum systems and control theory; it looks at what dynamics can happen with the use of external driving, and how this driving can be chosen to accomplish a desired goal. The first result looks at how a given quantum dissipator can be manipulated, using coherent controls, into replicating the action of a different type of noise. This results in no-go theorems for how noise can be transformed based on its isotropy, with applications in simulating open systems. Another way of doing simulations is to use only unitary dynamics over the system and a finite dimensional ancilla, and it is proved that there always exists a dilation Hamiltonian that replicates the noisy dynamics continuously in time. This also highlights the fact that adding controls on noise can result in a different evolution than if the controls were done on the under- lying system-environment level. A conjecture is introduced and studied which states that both approaches are equivalent in the special case of the controls commuting with the Lindbladian. A way around this difficulty is to use a quantum system to compute in situ which controls are best for achieving a desired task on itself. This problem is studied in the context of reaching entangling gates on a quantum simulator in order to upgrade it into a quantum computer. The experimental cost of doing so is found to be polynomial in the number of qubits in simulations. The same underlying principle is also used to find error correcting codes tailored to the dissipation in a system.

Sep 1, 20172 citations

Thermodynamically consistent dynamics of driven open quantum systems: from an autonomous framework to the semi-classical description

Roie Dann, Ronnie Kosloff

The structure of a thermodynamically consistent master equation for a driven system is obtained by imposing a set of thermodynamic postulates. The analysis is based on a time-independent autonomous construction, incorporating the drive as a large transient control quantum system. Under these assumptions, by partitioning the control and primary system we derive the semi-classical description. In this framework, the drive is incorporated as a time-dependent term in the primary system Hamiltonian. The resulting structure of the master equation is determined by a set of eigenoperators of the driven free dynamics. We demonstrate the theory by analyzing a qubit controlled by a single bosonic mode in a coherent state.

Dec 14, 20204 citations

Entropy-based formulation of thermodynamics in arbitrary quantum evolution

S. Alipour, A. T. Rezakhani, Aurélia Chenu +2 more

Given the evolution of an arbitrary open quantum system, we formulate a general and unambiguous method to separate the internal energy change of the system into an entropy-related contribution and a part causing no entropy change, identified as heat and work, respectively. We also demonstrate that heat and work admit geometric and dynamical descriptions by developing a universal dynamical equation for the given trajectory of the system. The dissipative and coherent parts of this equation contribute exclusively to heat and work, where the specific role of a work contribution from a counterdiabatic drive is underlined. Next we define an expression for the irreversible entropy production of the system which does not have explicit dependence on the properties of the ambient environment; rather, it depends on a set of the system's observables excluding its Hamiltonian and is independent of internal energy change. We illustrate our results with three examples.

arXiv:1912.01939Physical Review AApr 18, 202251 citations