The quantum regime of mechanical systems promises fascinating new fields of research both for applications and for fundamental physics. Quantum optics provides a well-developed toolbox to enter this regime. My talk will cover recent advances in quantum-opto-mechanical systems such as laser-cooling towards the quantum ground state. I will also discuss the prospects of generating quantum entanglement involving mechanical resonators, which is an important resource for quantum information processing and is also at he heart of Schrödinger's cat paradox.
The quantum regime of mechanical systems promises fascinating new fields of research both for applications and for fundamental physics. Quantum optics provides a well-developed toolbox to enter this regime. My talk will cover recent advances in quantum-opto-mechanical systems such as laser-cooling towards the quantum ground state. I will also discuss the prospects of generating quantum entanglement involving mechanical resonators, which is an important resource for quantum information processing and is also at he heart of Schrödinger's cat paradox.
The toolbox of quantum optics allows to achieve coherent quantum control over massive mechanical resonators by using radiation pressure of light inside optical cavities. Only recently, cavity-assisted ground state cooling of mechanical motion has been achieved both in the micro- and in the nanomechanical domain [1, 2]. Together with the strong coupling regime [3], this opens up a new parameter regime for macroscopic quantum physics with respect to size and mass of the objects under investigation. I will discuss the prospects of generating macroscopic quantum superposition states [4] and quantum entanglement [5], both for micromechanical interfaces for quantum information processing and for new tests of the foundations of quantum physics.
The toolbox of quantum optics allows to achieve coherent quantum control over massive mechanical resonators by using radiation pressure of light inside optical cavities. Only recently, cavity-assisted ground state cooling of mechanical motion has been achieved both in the micro- and in the nanomechanical domain [1, 2]. Together with the strong coupling regime [3], this opens up a new parameter regime for macroscopic quantum physics with respect to size and mass of the objects under investigation. I will discuss the prospects of generating macroscopic quantum superposition states [4] and quantum entanglement [5], both for micromechanical interfaces for quantum information processing and for new tests of the foundations of quantum physics.
Quantum opto- and electromechanical systems interface mechanical motion with the electromagnetic modes of optical resonators and microwave circuits. The capabilities and promise of these hybrid devices have been showcased through a variety of recent experimental advances that demonstrated exquisite control over the quantum state of solid-state mechanical objects. In this perspective, we offer an overview of the current state, as well as an outlook of the future directions, challenges, and opportunities for this growing field of research. We focus, in particular, on the prospects for ground state cooling of mechanical modes and their use in quantum circuits, transducers, and networks.
The quantum level interaction between light and mechanical systems has become a cutting-edge research with broad implications for fundamental physics, quantum information processing, and sensing. Quantum optomechanical systems allow for the precise control and modulation of light-matter interactions by coupling photons with mechanical resonators. Novel approaches to the manipulation of light and matter quantum states have been made possible by recent developments in the fabrication of ultra-sensitive mechanical devices and the achievement of strong coupling regimes. the most recent advancements in quantum optomechanics, such as the realization of non-classical states of light and mechanical motion, the improvement of quantum coherence, and the cooling of mechanical systems to their quantum ground state. possible uses in quantum memory, extremely accurate measurement systems, and basic quantum mechanical experiments. In order to create more reliable and scalable quantum networks, the study concludes by outlining potential future avenues for combining quantum optomechanical systems with other quantum technologies.
The ability to control the motion of mechanical systems through interaction with light has opened the door to a plethora of applications in fundamental and applied physics. With experiments routinely reaching the quantum regime, the focus has now turned towards creating and exploiting interesting non-classical states of motion and entanglement in optomechanical systems. Quantumness has also shifted from being the very reason why experiments are constructed to becoming a resource for the investigation of fundamental physics and the creation of quantum technologies. Here, by focusing on opto- and electromechanical platforms we review recent progress in quantum state preparation and entanglement of mechanical systems, together with applications to signal processing and transduction, quantum sensing and topological physics, as well as small-scale thermodynamics.
Quantum opto-mechanics is a fast moving, broad research field which aims to investigate and control the interaction of light and the quantized motion of mechanical objects and the coupling between them. This allows one to engineer the mechanical quantum state by controlling and measuring the electromagnetic field, and conversely, to control the dynamical evolution of the optical field via its interaction with a mechanical system. Mechanical resonators are accessible in many different shapes and sizes, from kilogram scales in experiments that test gravitational theories to micro- and nano-scales in resolved sideband regime, where the frequency of the mechanical resonator is larger than the bandwidth of the optical cavity. In this regime, it is possible to cool the mechanical object to the ground state which allows a high degree of control and the ability to prepare interesting non-classical states, states that could aid in investigating the quantum dynamics of macroscopic objects. The field of quantum opto-mechanics is a promising testbed for quantum control technologies, such as fundamental tests of quantum mechanics, ultra-sensitive quantum sensors for precise measurements, phonon lasing, mechanical memories with long lifetime and quantum information processing. Furthermore, experiments are progressing toward strong opto-mechanical coupling regimes with single photons. This creates a platform that can take advantage of the nonlinear optical interactions to generate highly non-classical states in such light-matter interfaces. Photonic systems working in the single photon regime will be promising for low power applications and also for implementations of quantum information and computation. Motivated by these applications, this thesis consists of theoretical studies in the context of single photonics. This includes investigating non-classical mechanical state generation and mechanically controlling the dynamical evolution of optical fields in the strong coupling regime single photon opto-mechanics and furthermore, proposing a quantum sensor using single photonics. In this regard, we employ three important formalisms to treat and measure open quantum systems with non-Gaussian input fields: the conditional and unconditional cascaded master equations, Fock-state master equations and input-output Langevin equations. In the context of opto-mechanics, the system to be investigated is composed of two optical cavities with a coupling modulated via a mechanical resonator. In one case, a sequence of single photons are irreversibly sent to one of the optical cavities. After photons go through the opto-mechanical interaction, photon counting measurements are performed on the cavity output, conditionally steering the mechanical state to a highly non-classical Fock state. Numerical calculations are performed to predict the experimental parameters needed to generate a mechanical Fock state before the mechanical object is thermalized. In another case, the same opto-mechanical scheme is employed to conversely modify the state of the optical mode by engineering the state of the mechanical degree of freedom. In this case, it is shown that the opto-mechanical system operates as an effective beam splitter for the input single photons, with a transmission that can be controlled by tuning the number of excitations in the bulk mechanical resonator. When the mechanical resonator has a small coherent amplitude it acts as a quantum control, entangling the optical and mechanical degrees of freedom. As the coherent amplitude of the resonator increases, it acts as a classical control for the input photons. Finally, we propose a novel multi-purpose sensor architecture that can be used for force, refractive index and possibly local temperature detection. In this scheme, two coupled cavities behave as an effective beam splitter. This sensor is based on fourth order interference (the Hong-Ou-Mandel effect) and requires a sequence of single photon pulses and consequently has low pulse power. Changes in the parameter to be measured induce variations in the effective beam splitter reflectivity and result in changes to the visibility of interference. We propose that this generic scheme could be implemented with coupled L3 photonic crystal cavities and find that this system, which only relies on photon coincidence detection and does not need any spectral resolution, can estimate forces as small as 10-7 Newtons and can measure one part per million change in refractive index using a very low input power of 10-10 W.