How Does Noise Affect a Quantum State?

Richard Bausch, Á. Stáhl

Shengyao Wu, Wenjie Liu, Zhiguo Qu

In order to improve the anti-noise performance of quantum teleportation, this paper proposes a novel dynamic quantum anti-noise scheme based on the quantum teleportation which transmits single qubit state using Bell state. Considering that quantum noise only acts on the transmitted qubit, i.e., the entangled state that Alice and Bob share in advance is affected by the noise, thus affecting the final transmission result. In this paper, a method for dynamically adjusting the shared entangled state according to the noise environment is proposed. By calculating the maximum fidelity of the output state to determine the shared entangled state, which makes the quantum teleportation be affected by the noise as little as possible. This paper calculates the fidelity of teleportation under four kinds of channel noise (amplitude damping, phase damping, bit flip and depolarizing noise). The results show that the scheme has a suppression effect on phase damping, bit flip and depolarizing noise under certain conditions. When the noise intensity is larger, the optimized efficiency is better.

Cao Shuai, Fang Mao-Fa, Zheng Xiao-Juan

It has recently been realized that quantum strategies have a great advantage over classical ones in quantum games. However, quantum states are easily affected by the quantum noise, resulting in decoherence. In this paper, we investigate the effect of quantum noise on a multiplayer quantum game with a certain strategic space, with all players affected by the same quantum noise at the same time. Our results show that in a maximally entangled state, a special Nash equilibrium appears in the range of 0≤p≤0.622 (p is the quantum noise parameter), and then disappears in the range of 0.622<p≤1. Increasing the amount of quantum noise leads to the reduction of the quantum player's payoff.

François Chapeau‐Blondeau

Andrea Aiello, Martin P. van Exter, Gerard Nienhuis +1 more

Muhammad Noman, Aqsa Mushtaq, Wei Cui

Abstract We investigate the dynamical maps of coherence, entanglement, and purity in two distinct three-qubit class states: the Werner (W-like) and Greeneberger–Horne–Zeillinger (GHZ-like) states. Utilizing a classical channel affected by Ornstein Uhlenbeck (OU) and Random Telegraph (RT) noise, we explore two scenarios: coupling two qubits with RT noise and one with OU noise, and vice versa . The preservation of coherence, entanglement, and purity is analyzed using the ℓ 1 norm of coherence, entanglement witness operation, and purity measures. Our results reveal that the considered dephasing channels lead to a decrease in initially encoded quantum correlations, even in the presence of Gaussian OU noise, which typically induces monotonic decay. The non-monotonic behavior and decay are primarily governed by the parameters of OU and RT noises, with the configuration where OU noise affects two qubits and RT noise affects the third being optimal for quantum correlation preservation. Comparing the two states, the GHZ-like state exhibits superior preservation under RT noise influencing two local fields and qubits, while the W-like state performs better when OU noise affects two qubits. Overall, the GHZ-like state shows enhanced revival characteristics compared to the W-like state.