Creation of Fock States in an Optical Cavity via Phonon-Photon Interaction

Byron Lowry, Bereket Berhane, S. Drakunov

Robert J. Schoelkopf

Xinchen Zhang, Nuo Wang, Zhaohua Tian +2 more

The preparation of Fock states, as a fundamental problem in the research of quantum optics and quantum information, still faces challenges in achieving both unconditional preparation and large photon numbers. Here, we study the deterministic generation of large Fock states through the nonlinear interaction in coupled optical-optomechanical cavities. Under the condition that the mechanical frequency is twice the optical coupling strength, and much larger than the optomechanical coupling strength, there occurs a nonlinear interaction among two optical eigenmodes and the mechanical mode, i.e., a photon is annihilated, accompanied by the creation of another photon together with a phonon, and vice versa. It is analytically proved that, through this interaction, Fock states | n 〉 and | 1 〉 will generate | n + 1 〉 at specific evolution times if the mechanical mode is initially on the ground state. In addition, numerical results show that Fock states | n 〉 and | p 〉 can also generate | n + p 〉 with the fidelities larger than 94% ( 1 < p ≤ n ≤ 40 ). The proposed mechanism achieves deterministic generation of large Fock states, which can be applied to quantum metrology and quantum simulation.

Andrew Shepherd, Ryan O. Behunin

Recognized as a potential resource for quantum technologies and a possible test bed for fundamental physics, the control and preparation of nonclassical states of mechanical oscillators have been explored extensively. Within optomechanics, quantum state synthesis can be realized by entangling photonic and phononic degrees of freedom followed by optical detection. Single-photon detection enables one of the most powerful forms of such heralded quantum state preparation, permitting the creation of single-phonon states when applied to conventional cavity optomechanical systems. As the complexity of optomechanical systems increases, single-photon detection may provide heralded access to a larger class of exotic quantum states. Here, we examine the quantum dynamics of optomechanical systems that permit forward Brillouin scattering, where a single-phonon mode mediates transitions between a collection of equally spaced optical resonances. Solving both the Schrodinger equation and the Lindblad master equation for this system, we find that initial states comprised of single photons or weak laser pulses evolve into complex quantum states where the frequency of single-photon states and the phonon occupation number are entangled. Physically, these interactions permit a single photon to scatter to lower frequencies, where phonon excitation occurs for each scattering event. Combining this result with frequency filtering, we show how single-photon detection can herald selected multiphonon Fock states, even in the presence of optical losses. We also present an approach for quantum tomography of the heralded phonon states, which in the form of a state swap from the phononic to photonic domain enables on-demand generation of multiphoton Fock states.

Botan Khani, Jay Gambetta, Felix Motzoi +1 more

S. Ya. Kilin, D. B. Horoshko, Dmitri S. Mogilevtsev