K. M. Jones - University of Queensland

K. M. Jones
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Name
K. M. Jones
Affiliation
University of Queensland
City
Saint Lucia
Country
Australia

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Nuclear Experiment (17)
 
Quantum Physics (10)
 
Mathematics - Group Theory (4)
 
Astrophysics (3)
 
Astrophysics of Galaxies (3)
 
Nuclear Theory (3)
 
Computer Science - Computation and Language (3)
 
Physics - Other (2)
 
Mathematics - Mathematical Physics (2)
 
Mathematics - Dynamical Systems (2)
 
Mathematics - Geometric Topology (2)
 
Mathematical Physics (2)
 
Physics - Statistical Mechanics (1)
 
Physics - Atomic Physics (1)
 
Physics - Mesoscopic Systems and Quantum Hall Effect (1)
 
Physics - Physics Education (1)
 
Physics - Optics (1)
 
Physics - Instrumentation and Detectors (1)
 
Nonlinear Sciences - Chaotic Dynamics (1)
 
Statistics - Applications (1)
 
Mathematics - Algebraic Topology (1)

Publications Authored By K. M. Jones

The SU(1,1) interferometer can be thought of as a Mach-Zehnder interferometer with its linear beamsplitters replaced with parametric nonlinear optical processes. We consider the cases of bright and vacuum-seeded SU(1,1) interferometers using intensity or homodyne detectors. A simplified, truncated scheme with only one nonlinear interaction is introduced, which not only beats conventional intensity detection with a bright seed, but can saturate the phase sensitivity bound set by the quantum Fisher information. Read More

An SU(1,1) interferometer replaces the beamsplitters in a Mach-Zehnder interferometer with nonlinear interactions and offers the potential of achieving high phase sensitivity in applications with low optical powers. We present a novel variation in which the second nonlinear interaction is replaced with balanced homodyne detection. The phase-sensing quantum state is a two-mode squeezed state produced by seeded four-wave-mixing in Rb vapor. Read More

Halo nuclei are excellent examples of few-body systems consisting of a core and weakly-bound halo nucleons. Where there is only one nucleon in the halo, as in 11Be, the many-body problem can be reduced to a two-body problem. The contribution of the 1s1/2 orbital to the ground state configuration in 11Be, characterized by the spectroscopic factor, S, has been extracted from direct reaction data by many groups over the past five decades with discrepant results. Read More

Many optical applications depend on amplitude modulating optical beams using devices such as acousto-optical modulators (AOMs) or optical choppers. Methods to add amplitude modulation (AM) often inadvertently impart phase modulation (PM) onto the light as well. While this PM is of no consequence to many phase-insensitive applications, phase-sensitive processes can be affected. Read More

Interacting galaxies are known to have higher global rates of star formation on average than normal galaxies, relative to their stellar masses. Using UV and IR photometry combined with new and published H-alpha images, we have compared the star formation rates of ~700 star forming complexes in 46 nearby interacting galaxy pairs with those of regions in 39 normal spiral galaxies. The interacting galaxies have proportionally more regions with high star formation rates than the spirals. Read More

Direct reaction techniques are powerful tools to study the single-particle nature of nuclei. Performing direct reactions on short-lived nuclei requires radioactive ion beams produced either via fragmentation or the Isotope Separation OnLine (ISOL) method. Some of the most interesting regions to study with direct reactions are close to the magic numbers where changes in shell structure can be tracked. Read More

2015Jul
Affiliations: 1St John's College, 2NRAO, 3University of Virginia, 4Spitzer Science Center/IPAC, 5LAM, Marseille, 6Spitzer Science Center/IPAC, 7University of Western Cape, 8Virginia Tech, 9University of Cambridge, 10University of Western Cape, 11University of Portsmouth, 12Open University, 13University of Sussex, 14Lisbon Observatory, 15University of Portsmouth, 16Tufts University

We combine a deep 0.5~deg$^2$, 1.4~GHz deep radio survey in the Lockman Hole with infrared and optical data in the same field, including the SERVS and UKIDSS near-infrared surveys, to make the largest study to date of the host galaxies of radio sources with typical radio flux densities $\sim 50 \;\mu$Jy. Read More

We fully describe the horofunction boundary $\partial_h L_2$ with the word metric associated with the generating set $\{t,at\}$ (i.e the metric arising in the Diestel-Leader graph $\text{DL}(2,2)$). The visual boundary $\partial_\infty L_2$ with this metric is a subset of $\partial_h L_2$. Read More

Although it is widely accepted that classical information cannot travel faster than the speed of light in vacuum, the behavior of quantum correlations and quantum information propagating through actively-pumped fast-light media has not been studied in detail. To investigate this behavior, we send one half of an entangled state of light through a gain-assisted fast-light medium and detect the remaining quantum correlations. We show that the quantum correlations can be advanced by a small fraction of the correlation time while the entanglement is preserved even in the presence of noise added by phase-insensitive gain. Read More

Working notes on setting up approximate dynamical systems and nonlinear eigenvalue problems, here embedded within the theory of complex nonlinear dynamics. Computations parallel those of linear quantum theory except that we use functional methods rather than Hilbert space. Read More

We introduce a simple deformed quantization prescription that interpolates the classical and quantum sectors of Weinberg's nonlinear quantum theory. The result is a novel classical limit where $\hbar$ is kept fixed while a dimensionless mesoscopic parameter, $\lambda\in[0,1]$, goes to zero. Unlike the standard classical limit, which holds good up to a certain timescale, ours is a precise limit incorporating true dynamical chaos, no dispersion, an absence of macroscopic superpositions and a complete recovery of the symplectic geometry of classical phase space. Read More

In 2003 Bieri and Geoghegan generalized the Bieri-Neuman-Strebel invariant $\Sigma^1$ by defining $\Sigma^1(\rho)$, $\rho$ an isometric action by a finitely generated group $G$ on a proper CAT(0) space $M$. In this paper, we show how the natural and well-known connection between Bass-Serre theory and covering space theory provides a framework for the calculation of $\Sigma^1(\rho)$ when $\rho$ is a cocompact action by $G = B \rtimes A$, $A$ a finitely generated group, on a locally finite Bass-Serre tree $T$ for $A$. This framework leads to a theorem providing conditions for including an endpoint in, or excluding an endpoint from, $\Sigma^1(\rho)$. Read More

The extraction of detailed nuclear structure information from transfer reactions requires reliable, well-normalized data as well as optical potentials and a theoretical framework demonstrated to work well in the relevant mass and beam energy ranges. It is rare that the theoretical ingredients can be tested well for exotic nuclei owing to the paucity of data. The halo nucleus Be-11 has been examined through the 10Be(d,p) reaction in inverse kinematics at equivalent deuteron energies of 12,15,18, and 21. Read More

Problem Roulette (PR) is a web-based study service at the University of Michigan that offers random-within-topic access to a large library of past exam problems in introductory physics courses. Built on public-private cloud computing infrastructure, PR served nearly 1000 students during Fall 2012 term, delivering more than 60,000 problem pages. The service complements that of commercial publishing houses by offering problems authored by local professors. Read More

A system of two microchannel-plate detectors has been successfully implemented for tracking projectile-fragmentation beams. The detectors provide interaction positions, angles, and arrival times of ions at the reaction target. The current design is an adaptation of an assembly used for low-energy beams ($\sim$1. Read More

Simulations of r-process nucleosynthesis require nuclear physics information for thousands of neutron-rich nuclear species from the line of stability to the neutron drip line. While arguably the most important pieces of nuclear data for the r-process are the masses and beta decay rates, individual neutron capture rates can also be of key importance in setting the final r-process abundance pattern. Here we consider the influence of neutron capture rates in forming the A~80 and rare earth peaks. Read More

Diestel-Leader graphs are neither hyperbolic nor CAT(0), so their visual boundaries may be pathological. Indeed, we show that for $d>2$, $\partial\text{DL}_d(q)$ carries the indiscrete topology. On the other hand, $\partial\text{DL}_2(q)$, while not Hausdorff, is $T_1$, totally disconnected, and compact. Read More

Transfer reactions are a powerful probe of the properties of atomic nuclei. When used in inverse kinematics with radioactive ion beams they can provide detailed information on the structure of exotic nuclei and can inform nucleosynthesis calculations. There are a number of groups around the world who use these reactions, usually with particle detection in large silicon arrays. Read More

Using a new state-dependent, $\lambda$-deformable, linear functional operator, ${\cal Q}_{\psi}^{\lambda}$, which presents a natural $C^{\infty}$ deformation of quantization, we obtain a uniquely selected non--linear, integro--differential Generalized Schr\"odinger equation. The case ${\cal Q}_{\psi}^{1}$ reproduces linear quantum mechanics, whereas ${\cal Q}_{\psi}^{0}$ admits an exact dynamic, energetic and measurement theoretic {\em reproduction} of classical mechanics. All solutions to the resulting classical wave equation are given and we show that functionally chaotic dynamics exists. Read More

Using a simple geometrical construction based upon the linear action of the Heisenberg--Weyl group we deduce a new nonlinear Schr\"{o}dinger equation that provides an exact dynamic and energetic model of any classical system whatsoever, be it integrable, nonintegrable or chaotic. Within our model classical phase space points are represented by equivalence classes of wavefunctions that have identical position and momentum expectation values. Transport of these equivalence classes without dispersion leads to a system of wavefunction dynamics such that the expectation values track classical trajectories {\em precisely\/} for arbitrarily long times. Read More

Optical phase measurement is a simple example of a quantum--limited measurement problem with important applications in metrology such as gravitational wave detection. The formulation of optimal strategies for such measurements is an important test-bed for the development of robust statistical methods for instrument evaluation. However, the class of possible distributions exhibits extreme pathologies not commonly encountered in conventional statistical analysis. Read More

The best examples of halo nuclei, exotic systems with a diffuse nuclear cloud surrounding a tightly-bound core, are found in the light, neutron-rich region, where the halo neutrons experience only weak binding and a weak, or no, potential barrier. Modern direct reaction measurement techniques provide powerful probes of the structure of exotic nuclei. Despite more than four decades of these studies on the benchmark one-neutron halo nucleus Be-11, the spectroscopic factors for the two bound states remain poorly constrained. Read More

Given an action by a finitely generated group G on a locally finite tree T, we view points of the visual boundary \partialT as directions in T and use {\rho} to lift this sense of direction to G. For each point E \in \partialT, this allows us to ask if G is (n - 1)-connected "in the direction of E". The invariant {\Sigma}^n({\rho}) \subseteq \partialT then records the set of directions in which G is (n-1)-connected. Read More

The (d,p) neutron transfer and (d,d) elastic scattering reactions were measured in inverse kinematics using a radioactive ion beam of 132Sn at 630 MeV. The elastic scattering data were taken in a region where Rutherford scattering dominated the reaction, and nuclear effects account for less than 8% of the cross section. The magnitude of the nuclear effects was found to be independent of the optical potential used, allowing the transfer data to be normalized in a reliable manner. Read More

Neutron-unbound resonant states of 11Be were populated in neutron knock-out reactions from 12Be and identified by 10Be-n coincidence measurements. A resonance in the decay-energy spectrum at 80(2) keV was attributed to a highly excited unbound state in 11Be at 3.949(2) MeV decaying to the 2+ excited state in 10Be. Read More

Atomic nuclei have a shell structure where nuclei with 'magic numbers' of neutrons and protons are analogous to the noble gases in atomic physics. Only ten nuclei with the standard magic numbers of both neutrons and protons have so far been observed. The nuclear shell model is founded on the precept that neutrons and protons can move as independent particles in orbitals with discrete quantum numbers, subject to a mean field generated by all the other nucleons. Read More

We present an experimental realization of a low-noise, phase-insensitive optical amplifier using a four-wave mixing interaction in hot Rb vapor. Performance near the quantum limit for a range of amplifier gains, including near unity, can be achieved. Such low-noise amplifiers are essential for so-called quantum cloning machines and are useful in quantum information protocols. Read More

The low-lying level structure of the unbound system $^{16}$B has been investigated via single-proton removal from a 35 MeV/nucleon $^{17}$C beam. The coincident detection of the beam velocity $^{15}$B fragment and neutron allowed the relative energy of the in-flight decay of $^{16}$B to be reconstructed. The resulting spectrum exhibited a narrow peak some 85 keV above threshold. Read More

Evaporation residue and fission cross sections of radioactive $^{132}$Sn on $^{64}$Ni were measured near the Coulomb barrier. A large sub-barrier fusion enhancement was observed. Coupled-channel calculations including inelastic excitation of the projectile and target, and neutron transfer are in good agreement with the measured fusion excitation function. Read More

We demonsatrate an all optical technique to evaporatively produce sodium Bose-Einstein condensates (BEC). We use a crossed-dipole trap formed from light near 1060 nm, and a simple ramp of the intensity to force evaporation. In addition, we introduce photoassociation as diagnostic of the trap loading process, and show that it can be used to detect the onset of Bose-Einstein condensation. Read More

By driving photoassociation transitions we form electronically excited molecules (Na$_2^*$) from ultra-cold (50-300 $\mu$K) Na atoms. Using a second laser to drive transitions from the excited state to a level in the molecular ground state, we are able to split the photoassociation line and observe features with a width smaller than the natural linewidth of the excited molecular state. The quantum interference which gives rise to this effect is analogous to that which leads to electromagnetically induced transparency in three level atomic $\Lambda$ systems, but here one of the ground states is a pair of free atoms while the other is a bound molecule. Read More

The phase transition from a superfluid to a Mott insulator has been observed in a $^{23}$Na Bose-Einstein condensate. A dye laser detuned $\approx 5$nm red of the Na $3^2$S$ \to 3^2$P$_{1/2}$ transition was used to form the three dimensional optical lattice. The heating effects of the small detuning as well as the three-body decay processes constrained the timescale of the experiment. Read More

Studies of the 16O(9Be,alpha 7Be)14C, 7Li(9Be,alpha 7Li)5He and 7Li(9Be,alpha alpha t)5He reactions at E(beam)=70 and 55 MeV have been performed using resonant particle spectroscopy techniques. The 11C excited states decaying into alpha+7Be(gs) are observed between 8.5 and 13. Read More

Studies of the 16O(9Be,alpha7Be)14C and 7Li(9Be,alpha7Li)5He reactions at E{beam}=70 MeV have been performed using resonant particle spectroscopy techniques. The 11C excited states decaying into alpha+7Be(gs) are observed at 8.65, 9. Read More

Ultra-cold neutrons (UCN), neutrons with energies low enough to be confined by the Fermi potential in material bottles, are playing an increasing role in measurements of fundamental properties of the neutron. The ability to manipulate UCN with material guides and bottles, magnetic fields, and gravity can lead to experiments with lower systematic errors than have been obtained in experiments with cold neutron beams. The UCN densities provided by existing reactor sources limit these experiments. Read More

A study of the 7Li(9Be,4He9Be)3H reaction at E{beam}=70 MeV has been performed using resonant particle spectroscopy techniques and provides a measurement of alpha-decaying states in 13C. Excited states are observed at 12.0, 13. Read More

A study of the 7Li(9Be,4He 10Be)2H reaction at E{beam}=70 MeV has been performed using resonant particle spectroscopy techniques and provides the first measurements of alpha-decaying states in 14C. Excited states are observed at 14.7, 15. Read More

2003Mar
Affiliations: 1University of Queensland, 2Australia Telescope National Facility, 3University of Queensland
Category: Astrophysics

We present the results of ATCA HI line and 20-cm radio continuum observations of the galaxy Quartet NGC 6845. The HI emission extends over all four galaxies but can only be associated clearly with the two spiral galaxies, NGC 6845A and B, which show signs of strong tidal interaction. We derive a total HI mass of at least 1. Read More

2002Nov
Affiliations: 1ATNF, 2ATNF, 3University of Queensland
Category: Astrophysics

ATCA HI and radio continuum observations of the peculiar southern galaxy IC2554 and its surroundings reveal typical signatures of an interacting galaxy group. We detected a large HI cloud between IC2554 and the elliptical galaxy NGC3136B. The gas dynamics in IC2554 itself, which is sometimes described as a colliding pair, are surprisingly regular, whereas NGC3136B was not detected. Read More

We report on the formation of ultra-cold Na$_2$ molecules using single-photon photoassociation of a Bose-Einstein condensate. The photoassociation rate, linewidth and light shift of the J=1, $v=135$ vibrational level of the \mterm{A}{1}{+}{u} molecular bound state have been measured. We find that the photoassociation rate constant increases linearly with intensity, even where it is predicted that many-body effects might limit the rate. Read More

We present the results of new radio interferometer HI line observations for the merging galaxy pair NGC 4038/9 (`The Antennae'), obtained using the Australia Telescope Compact Array. The results improve substantially on those of van der Hulst (1979) and show in detail the two merging galactic disks and the two tidal tails produced by their interaction. The small edge-on spiral dwarf galaxy ESO 572-G045 is also seen near the tip of the southern tail, but distinct from it. Read More

1998May
Affiliations: 1Computer Laboratory, University of Cambridge

This position paper suggests that progress with automatic summarising demands a better research methodology and a carefully focussed research strategy. In order to develop effective procedures it is necessary to identify and respond to the context factors, i.e. Read More

1997Feb

Information technology should have much to offer linguistics, not only through the opportunities offered by large-scale data analysis and the stimulus to develop formal computational models, but through the chance to use language in systems for automatic natural language processing. The paper discusses these possibilities in detail, and then examines the actual work that has been done. It is evident that this has so far been primarily research within a new field, computational linguistics, which is largely motivated by the demands, and interest, of practical processing systems, and that information technology has had rather little influence on linguistics at large. Read More

Given the present state of work in natural language processing, this address argues first, that advance in both science and applications requires a revival of concern about what language is about, broadly speaking the world; and second, that an attack on the summarising task, which is made ever more important by the growth of electronic text resources and requires an understanding of the role of large-scale discourse structure in marking important text content, is a good way forward. Read More

Puts forward a complete scenario for interpreting nonlinear field theories highlighting the role played by gravitational self--energy in enabling a consistent revival of the Schroedinger approach to unifying micro and macro physics. Read More