P. F. Barker
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View article: Optical centrifuge for nanoparticles
Optical centrifuge for nanoparticles Open
We study theoretically the creation of an optical centrifuge for the controlled rotation of levitated nanorotors within an optical tweezer. The optical centrifuge's motion is simulated by rapidly rotating the linear polarization of the tig…
View article: Levitated optomechanics with cylindrically polarized vortex beams
Levitated optomechanics with cylindrically polarized vortex beams Open
Optically levitated and cooled nanoparticles are a new quantum system whose application to the creation of non-classical states of motion and quantum limited sensing is fundamentally limited by recoil and bulk heating. We study the creatio…
View article: A Spin-Based Pathway to Testing the Quantum Nature of Gravity
A Spin-Based Pathway to Testing the Quantum Nature of Gravity Open
A key open problem in physics is the correct way to combine gravity (described by general relativity) with everything else (described by quantum mechanics). This problem suggests that general relativity and possibly also quantum mechanics …
View article: Mass-spectrometry via oscillatory motion in deep pulsed optical lattices
Mass-spectrometry via oscillatory motion in deep pulsed optical lattices Open
We describe a new optical diagnostic for determining the composition of gases by measuring the motion of atoms and molecules trapped within very deep optical lattices. This non-resonant method is analogous to conventional Raman scattering,…
View article: Dark matter searches with levitated sensors
Dark matter searches with levitated sensors Open
Motivated by the current interest in employing quantum sensors on Earth and in space to conduct searches for new physics, we provide a perspective on the suitability of large-mass levitated optomechanical systems for observing dark matter …
View article: Optimal superpositions for particle detection via quantum phase
Optimal superpositions for particle detection via quantum phase Open
Exploiting quantum mechanics for sensing offers unprecedented possibilities. State-of-the-art proposals for novel quantum sensors often rely on the creation of large superpositions and generally detect a field. However, what is the optimal…
View article: Sensing directional noise baths in levitated optomechanics
Sensing directional noise baths in levitated optomechanics Open
Optomechanical devices are being harnessed as sensors of ultraweak forces for applications ranging from inertial sensing to the search for the elusive dark matter. For the latter, there is a focus on detection of either higher energy singl…
View article: Dark Matter Searches with Levitated Sensors
Dark Matter Searches with Levitated Sensors Open
Motivated by the current interest in employing quantum sensors on Earth and in space to conduct searches for new physics, we provide a perspective on the suitability of large-mass levitated optomechanical systems for observing dark matter …
View article: Levitodynamic spectroscopy for single nanoparticle characterisation
Levitodynamic spectroscopy for single nanoparticle characterisation Open
Fast detection and characterization of single nanoparticles such as viruses, airborne aerosols and colloidal particles are considered to be particularly important for medical applications, material science and atmospheric physics. In parti…
View article: A levitated atom-nanosphere hybrid quantum system
A levitated atom-nanosphere hybrid quantum system Open
Near-field, radially symmetric optical potentials supported by a levitated nanosphere can be used for sympathetic cooling and for creating a bound nanosphere-atom system analogous to a large molecule. We demonstrate that the long range, Co…
View article: Optimal Superpositions for Particle Detection via Quantum Phase
Optimal Superpositions for Particle Detection via Quantum Phase Open
Exploiting quantum mechanics for sensing offers unprecedented possibilities. State of the art proposals for novel quantum sensors often rely on the creation of large superpositions and generally detect a field. However, what is the optimal…
View article: Sensing microscopic directional noise baths with an optically cooled and levitated nanoparticle
Sensing microscopic directional noise baths with an optically cooled and levitated nanoparticle Open
Optomechanical devices are being harnessed as sensors of ultraweak forces for applications ranging from inertial sensing to the search for the elusive dark matter. For the latter, there is a focus on detection of either higher energy singl…
View article: Controlling mode orientations and frequencies in levitated cavity optomechanics
Controlling mode orientations and frequencies in levitated cavity optomechanics Open
Cavity optomechanics offers quantum ground state cooling, control and measurement of small mechanical oscillators. However optomechanical backactions disturb the oscillator motions: they shift mechanical frequencies and, for a levitated os…
View article: Measurement of single nanoparticle anisotropy by laser induced optical alignment and Rayleigh scattering for determining particle morphology
Measurement of single nanoparticle anisotropy by laser induced optical alignment and Rayleigh scattering for determining particle morphology Open
We demonstrate the measurement of nanoparticle anisotropy by angularly resolved Rayleigh scattering of single optical levitated particles that are oriented in space via the trapping light in vacuum. This technique is applied to a range of …
View article: Research campaign: Macroscopic quantum resonators (MAQRO)
Research campaign: Macroscopic quantum resonators (MAQRO) Open
The objective of the proposed macroscopic quantum resonators (MAQRO) mission is to harness space for achieving long free-fall times, extreme vacuum, nano-gravity, and cryogenic temperatures to test the foundations of physics in macroscopic…
View article: Measurement of single nanoparticle anisotropy by laser induced optical alignment and Rayleigh scattering for determining particle morphology
Measurement of single nanoparticle anisotropy by laser induced optical alignment and Rayleigh scattering for determining particle morphology Open
We demonstrate the measurement of nanoparticle shape by angularly resolved Rayleigh scattering of single optical levitated particles that are oriented in space via the trapping light in vacuum. This technique is applied to a range of parti…
View article: Entanglement based tomography to probe new macroscopic forces
Entanglement based tomography to probe new macroscopic forces Open
Quantum entanglement provides a novel way to test short distance physics in the nonrelativistic regime. We will provide a protocol to potentially test new physics by bringing two charged massive particle interferometers adjacent to each ot…
View article: Cavity optomechanics in a fiber cavity: the role of stimulated Brillouin scattering
Cavity optomechanics in a fiber cavity: the role of stimulated Brillouin scattering Open
We study the role of stimulated Brillouin scattering in a fiber cavity by numerical simulations and a simple theoretical model and find good agreement between experiment, simulation and theory. We also investigate an optomechanical system …
View article: Imaging-based feedback cooling of a levitated nanoparticle
Imaging-based feedback cooling of a levitated nanoparticle Open
Imaging-based detection of the motion of levitated nanoparticles complements a widely used interferometric detection method, providing a precise and robust way to estimate the position of the particle. Here, we demonstrate a camera-based f…
View article: Simultaneous cooling of all six degrees of freedom of an optically levitated nanoparticle by elliptic coherent scattering
Simultaneous cooling of all six degrees of freedom of an optically levitated nanoparticle by elliptic coherent scattering Open
We report on strong cooling and orientational control of all translational and angular degrees of freedom of a nanoparticle levitated in an optical trap in high vacuum. The motional cooling and control of all six degrees of freedom of a na…
View article: Entanglement based tomography to probe new macroscopic forces
Entanglement based tomography to probe new macroscopic forces Open
Quantum entanglement provides a novel way to test short distance physics in the non-relativistic regime. We will provide a protocol to {\it potentially} test new physics by bringing two charged massive particle interferometers adjacent to …
View article: MAQRO -- BPS 2023 Research Campaign Whitepaper
MAQRO -- BPS 2023 Research Campaign Whitepaper Open
The objective of the proposed MAQRO mission is to harness space for achieving long free-fall times, extreme vacuum, nano-gravity, and cryogenic temperatures to test the foundations of physics in macroscopic quantum experiments. This will r…
View article: Sympathetic cooling and squeezing of two co-levitated nanoparticles
Sympathetic cooling and squeezing of two co-levitated nanoparticles Open
Levitated particles are an ideal tool for measuring weak forces and investigating quantum mechanics in macroscopic objects. Arrays of two or more of these particles have been suggested for improving force sensitivity and entangling macrops…
View article: Creating atom-nanoparticle quantum superpositions
Creating atom-nanoparticle quantum superpositions Open
A nanoscale object evidenced in a nonclassical state of its center of mass will hugely extend the boundaries of quantum mechanics. To obtain a practical scheme for the same, we exploit a hitherto unexplored coupled system: an atom and a na…
View article: Performance and limits of feedback cooling methods for levitated oscillators: A direct comparison
Performance and limits of feedback cooling methods for levitated oscillators: A direct comparison Open
Cooling the centre-of-mass motion is an important tool for levitated optomechanical systems, but it is often not clear which method can practically reach lower temperatures for a particular experiment. We directly compare the parametric an…
View article: Master-equation treatment of nonlinear optomechanical systems with optical loss
Master-equation treatment of nonlinear optomechanical systems with optical loss Open
Open-system dynamics play a key role in the experimental and theoretical\nstudy of cavity optomechanical systems. In many cases, the quantum Langevin\nequations have enabled excellent models for optical decoherence, yet a\nmaster-equation …
View article: ODP Leg 178, Hole 1096C - Well Logging Data
ODP Leg 178, Hole 1096C - Well Logging Data Open
Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, …
View article: ODP Leg 178, Hole 1103A - Well Logging Data
ODP Leg 178, Hole 1103A - Well Logging Data Open
Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, …
View article: ODP Leg 178, Hole 1103A - Well Logging Data
ODP Leg 178, Hole 1103A - Well Logging Data Open
Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, …
View article: ODP Leg 178, Hole 1095B - Well Logging Data
ODP Leg 178, Hole 1095B - Well Logging Data Open
Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, …