57 research outputs found
Phonon routing in integrated optomechanical cavity-waveguide systems
The mechanical properties of light have found widespread use in the
manipulation of gas-phase atoms and ions, helping create new states of matter
and realize complex quantum interactions. The field of cavity-optomechanics
strives to scale this interaction to much larger, even human-sized mechanical
objects. Going beyond the canonical Fabry-Perot cavity with a movable mirror,
here we explore a new paradigm in which multiple cavity-optomechanical elements
are wired together to form optomechanical circuits. Using a pair of
optomechanical cavities coupled together via a phonon waveguide we demonstrate
a tunable delay and filter for microwave-over-optical signal processing. In
addition, we realize a tight-binding form of mechanical coupling between
distant optomechanical cavities, leading to direct phonon exchange without
dissipation in the waveguide. These measurements indicate the feasibility of
phonon-routing based information processing in optomechanical crystal
circuitry, and further, to the possibility of realizing topological phases of
photons and phonons in optomechanical cavity lattices.Comment: 16 pages, 7 figure
A Nanoscale Parametric Feedback Oscillator
We describe and demonstrate a new oscillator topology, the parametric feedback oscillator (PFO). The PFO paradigm is applicable to a wide variety of nanoscale devices and opens the possibility of new classes of oscillators employing innovative frequency-determining elements, such as nanoelectromechanical systems (NEMS), facilitating integration with circuitry and system-size reduction. We show that the PFO topology can also improve nanoscale oscillator performance by circumventing detrimental effects that are otherwise imposed by the strong device nonlinearity in this size regime
Two-dimensional optomechanical crystal cavity with high quantum cooperativity
Optomechanical systems offer new opportunities in quantum information processing and quantum sensing. Many solid-state quantum devices operate at millikelvin temperaturesāhowever, it has proven challenging to operate nanoscale optomechanical devices at these ultralow temperatures due to their limited thermal conductance and parasitic optical absorption. Here, we present a two-dimensional optomechanical crystal resonator capable of achieving large cooperativity C and small effective bath occupancy n_b, resulting in a quantum cooperativity C_(eff) ā” C/n_b > 1 under continuous-wave optical driving. This is realized using a two-dimensional phononic bandgap structure to host the optomechanical cavity, simultaneously isolating the acoustic mode of interest in the bandgap while allowing heat to be removed by phonon modes outside of the bandgap. This achievement paves the way for a variety of applications requiring quantum-coherent optomechanical interactions, such as transducers capable of bi-directional conversion of quantum states between microwave frequency superconducting quantum circuits and optical photons in a fiber optic network
Collapse and Revival of an Artificial Atom Coupled to a Structured Photonic Reservoir
A structured electromagnetic reservoir can result in novel dynamics of quantum emitters. In particular, the reservoir can be tailored to have a memory of past interactions with emitters, in contrast to memory-less Markovian dynamics of typical open systems. In this Article, we investigate the non-Markovian dynamics of a superconducting qubit strongly coupled to a superconducting slow-light waveguide reservoir. Tuning the qubit into the spectral vicinity of the passband of this waveguide, we find non-exponential energy relaxation as well as substantial changes to the qubit emission rate. Further, upon addition of a reflective boundary to one end of the waveguide, we observe revivals in the qubit population on a timescale 30 times longer than the inverse of the qubit's emission rate, corresponding to the round-trip travel time of an emitted photon. By tuning of the qubit-waveguide interaction strength, we probe a crossover between Markovian and non-Markovian qubit emission dynamics. These attributes allow for future studies of multi-qubit circuits coupled to structured reservoirs, in addition to constituting the necessary resources for generation of multiphoton highly entangled states
Collapse and Revival of an Artificial Atom Coupled to a Structured Photonic Reservoir
A structured electromagnetic reservoir can result in novel dynamics of quantum emitters. In particular, the reservoir can be tailored to have a memory of past interactions with emitters, in contrast to memory-less Markovian dynamics of typical open systems. In this Article, we investigate the non-Markovian dynamics of a superconducting qubit strongly coupled to a superconducting slow-light waveguide reservoir. Tuning the qubit into the spectral vicinity of the passband of this waveguide, we find non-exponential energy relaxation as well as substantial changes to the qubit emission rate. Further, upon addition of a reflective boundary to one end of the waveguide, we observe revivals in the qubit population on a timescale 30 times longer than the inverse of the qubit's emission rate, corresponding to the round-trip travel time of an emitted photon. By tuning of the qubit-waveguide interaction strength, we probe a crossover between Markovian and non-Markovian qubit emission dynamics. These attributes allow for future studies of multi-qubit circuits coupled to structured reservoirs, in addition to constituting the necessary resources for generation of multiphoton highly entangled states
Harnessing Fluctuations in Thermodynamic Computing via Time-Reversal Symmetries
We experimentally demonstrate that highly structured distributions of work
emerge during even the simple task of erasing a single bit. These are
signatures of a refined suite of time-reversal symmetries in distinct
functional classes of microscopic trajectories. As a consequence, we introduce
a broad family of conditional fluctuation theorems that the component work
distributions must satisfy. Since they identify entropy production, the
component work distributions encode both the frequency of various mechanisms of
success and failure during computing, as well giving improved estimates of the
total irreversibly-dissipated heat. This new diagnostic tool provides strong
evidence that thermodynamic computing at the nanoscale can be constructively
harnessed. We experimentally verify this functional decomposition and the new
class of fluctuation theorems by measuring transitions between flux states in a
superconducting circuit
Nonequilibrium thermodynamics of erasure with superconducting flux logic
We implement a thermal-fluctuation-driven logical bit reset on a superconducting flux logic cell. We show that the logical state of the system can be continuously monitored with only a small perturbation to the thermally activated dynamics at 500 mK. We use the trajectory information to derive a single-shot estimate of the work performed on the system per logical cycle. We acquire a sample of 10āµ erasure trajectories per protocol and show that the work histograms agree with both microscopic theory and global fluctuation theorems. The results demonstrate how to design and diagnose complex, high-speed, and thermodynamically efficient computing using superconducting technology
Recommended from our members
Complex dynamical networks constructed with fully controllable nonlinear nanomechanical oscillators
Control of the global parameters of complex networks has been explored experimentally in a variety of contexts. Yet, the more difficult prospect of realizing arbitrary network architectures, especially analog physical networks that provide dynamical control of individual nodes and edges, has remained elusive. Given the vast hierarchy of time scales involved, it also proves challenging to measure a complex networkās full internal dynamics. These span from the fastest nodal dynamics to very slow epochs over which emergent global phenomena, including network synchronization and the manifestation of exotic steady states, eventually emerge. Here, we demonstrate an experimental system that satisfies these requirements. It is based upon modular, fully controllable, nonlinear radio frequency nanomechanical oscillators, designed to form the nodes of complex dynamical networks with edges of arbitrary topology. The dynamics of these oscillators and their surrounding network are analog and continuous-valued and can be fully interrogated in real time. They comprise a piezoelectric nanomechanical membrane resonator, which serves as the frequency-determining element within an electrical feedback circuit. This embodiment permits network interconnections entirely within the electrical domain and provides unprecedented node and edge control over a vast region of parameter space. Continuous measurement of the instantaneous amplitudes and phases of every constituent oscillator node are enabled, yielding full and detailed network data without reliance upon statistical quantities. We demonstrate the operation of this platform through the real-time capture of the dynamics of a three-node ring network as it evolves from the uncoupled state to full synchronization
- ā¦