Macroscopic mechanical oscillator is herded into a Schrödinger cat state

Alex Lopatka

A new demonstration of a famous thought experiment has coaxed a classical 16 µg cluster of atoms to behave like a quantum object.

Jin‐Feng Huang, Jie‐Qiao Liao, Lin Tian

Ye‐Xiong Zeng, Jian Shen, Ming‐Song Ding +1 more

Schrödinger cat states, as typical nonclassical states, are very sensitive to the decoherence effects so that swapping these states is a challenge. Here, we propose a reliable scheme to realize the swapping of macroscopic Schrödinger cat state and suppress the decoherence effect in a feedback-controlled optomechanical system that consists of a optical cavity and two mechanical oscillators. Our protocol is composed of three steps. First, we squeeze a mechanical Schrödinger cat state before the state swapping. Then, we complete the state swapping between the two mechanical modes via indirect interaction. Finally, the target mechanical oscillator obtains the Schrödinger cat state by an antisqueezing process. To confirm the superior performance of the protocol, we simulate the whole dynamics of the state transfer and analyze the influence of the squeezed parameters. The corresponding numerical and analytical results show that this approach can be used to reduce the effects of decoherence, which suggests that our state swapping proposal is effective and feasible.

A. Metelmann

Marius Bild, Matteo Fadel, Yu Yang +4 more

According to quantum mechanics, a physical system can be in any linear superposition of its possible states. Although the validity of this principle is routinely validated for microscopic systems, it is still unclear why we do not observe macroscopic objects to be in superpositions of states that can be distinguished by some classical property. Here we demonstrate the preparation of a mechanical resonator in Schrödinger cat states of motion, where the ∼10 17 constituent atoms are in a superposition of two opposite-phase oscillations. We control the size and phase of the superpositions and investigate their decoherence dynamics. Our results offer the possibility of exploring the boundary between the quantum and classical worlds and may find applications in continuous-variable quantum information processing and metrology with mechanical resonators.

Konrad W. Lehnert