Quantum Control and Quantum Entanglement

Aikaterini Mandilara

Dong Daoyi, Zonghai Chen

A scheme of quantum feedback control in which entanglement swapping is used to construct quantum feedback controller is proposed. The output state of the system to be controlled is entangled with the quantum state of a particle near the actuator through entanglement swapping, which constructs a quantum feedback channel, and two pairs of entangled states, two entanglement swapping processes and a unitary transformer together constitute a quantum controller. This feedback strategy can perform some tasks, such as remote control of entangled states and distant feedback of quantum states, which are not possible using quantum control with classical feedback.

H. Wang, M. Mariantoni, Radoslaw C. Bialczak +12 more

Quantum entanglement, one of the defining features of quantum mechanics, has been demonstrated in a variety of nonlinear spinlike systems. Quantum entanglement in linear systems has proven significantly more challenging, as the intrinsic energy level degeneracy associated with linearity makes quantum control more difficult. Here we demonstrate the quantum entanglement of photon states in two independent linear microwave resonators, creating N-photon NOON states (entangled states |N0> + |0N>) as a benchmark demonstration. We use a superconducting quantum circuit that includes Josephson qubits to control and measure the two resonators, and we completely characterize the entangled states with bipartite Wigner tomography. These results demonstrate a significant advance in the quantum control of linear resonators in superconducting circuits.

Dik Bouwmeester

YamamotoNaoki, MikamiTomoaki

Jincheng Zhang

Quantum entanglement, a bizarre phenomenon where two or more particles become linked and share the same fate no matter how far apart they are, holds immense promise for revolutionizing computation and communication. This paper explores the development of a novel quantum control matrix, "Quantum Entanglement Control Matrix" (QECM), which leverages the unique properties of entanglement to achieve precise control over quantum systems. The QECM's core mechanism centers around manipulating entangled states to encode and transmit quantum information, offering a pathway to enhanced quantum information processing and secure communication. We detail the algorithm's design, its potential advantages, and the challenges involved in translating this theoretical framework into a practical implementation.