Mapping properties for the Bargmann transform on modulation spaces

We investigate mapping properties for the Bargmann transform and prove that this transform is isometric and bijective from modulation spaces to convenient Banach spaces of analytic functions.Comment: Pre-version, 21 page

Tunable entanglement generation for mobile-electron spin qubits

Recent studies have shown that linear electron optics can be used to generate entangled two-particle states from nonentangled ones if additional measurements of charge or parity are performed. We have investigated such nondeterministic entanglement production in electronic versions of the Mach-Zehnder interferometer, where spin-dependent interference occurs due to the presence of electric-field tunable Rashba spin splitting. Adjustment of the spin-precession length turns out to switch the entangler on and off, as well as control the detailed form of entangled output states.Comment: 3+ pages, 3 figures, RevTex4, v3: figures improved + references added, to appear in Appl. Phys. Let

The flavour asymmetry of polarized anti-quarks in the nucleon

We present a study of the flavour asymmetry of polarized anti-quarks in the nucleon using the meson cloud model. We include contributions both from the vector mesons and the interference terms of pseudoscalar and vector mesons. Employing the bag model, we first give the polarized valence quark distribution of the $\rho$ meson and the interference distributions. Our calculations show that the interference effect mildly increases the prediction for \Delta \dbar(x)-\Delta \ubar(x) at intermediate $x$ region. We also discuss the contribution of `Pauli blocking' to the asymmetry.Comment: 22 pages, LaTex, 5 PS figures. Version to appear in Eur. Phys. J. C. An appendix is added for expressions for the helicity dependent fluctuation functions. An error in the programme for fluctuation function f_{(\pi\rho)\Delta /N} is corrected, which increases numerical results by about 10%. Unchanged conclusion

Strangeness in the Meson Cloud Model

I review progress in calculating strange quark and antiquark distributions of the nucleon using the meson cloud model. This progress parallels that of the meson cloud model, which is now a useful theoretical basis for understanding symmetry breaking in nucleon parton distribution functions. I examine the breaking of symmetries involving strange quarks and antiquarks, including quark - antiquark symmetry in the sea, SU(3) flavour symmetry and SU(6) spin-flavour symmetry.Comment: 6 pages, 4 figures. Talk given at workshop "Achievements and New Directions in Subatomic Physics: Workshop in honour of Tony Thomas' 60th birthday," CSSM, Adelaide, South Australia, 15 - 19 February 2010

g1(x) and g2(x) in the Meson Cloud Model

We calculate the spin dependent structure functions g1(x) and g2(x) of the proton and neutron. Our calculation uses the meson cloud model of nucleon structure and includes the effects of kinematic terms which mix transverse and longitudinal spin components. We find small corrections to the nucleon structure functions, however these are significant for the neutron.Comment: 4 pages, contribution to DIS 05, Madison, Wisconsi

Strange sea distributions of the nucleon

The strange and antistrange quark distributions of the nucleon are less constrained by experimental data than the non-strange quark sea. The combination of light quark sea distributions, \Delta(x)=\dbar(x)+\ubar(x)-s(x)-\sbar(x), originates mainly from non-perturbative processes and can be calculated using non-perturbative models of the nucleon. We have calculated $\Delta(x)$ using the meson cloud model, which, when combined with the relatively well known non-strange light antiquark distributions obtained from global analysis of available experimental data, enables us to make new estimates of the total strange sea distributions of the nucleon and the strange sea suppression factor.Comment: version published in J. Phys. G, 14 pages, 3 figure

Comparison of gluon flux-tube distributions for quark-diquark and quark-antiquark hadrons

The distribution of gluon fields in hadrons is of fundamental interest in QCD. Using lattice QCD we have observed the formation of gluon flux tubes within 3 quark (baryon) and quark plus antiquark (meson) systems for a wide variety of spatial distributions of the color sources. In particular we have investigated three quark configurations where two of the quarks are close together and the third quark is some distance away, which approximates a quark plus diquark string. We find that the string tension of the quark-diquark string is the same as that of the quark-antiquark string on the same lattice. We also compare the longitudinal and transverse profiles of the gluon flux tubes for both sets of strings, and find them to be of similar radii and to have similar vacuum suppression.Comment: 6 pages, 9 figures and 1 tabl

Reliability of Lower Limb Motor Evoked Potentials in Stroke and Healthy Populations: How Many Responses Are Needed?

Objective To determine the intra- and inter-session reliability of motor evoked potential (MEP) size parameters in the lower limb of patients with stroke, focussing on the number of MEPs collected and the method of measuring MEP size. Methods Transcranial magnetic stimulation was used to elicit MEPs in the soleus muscle of patients with stroke (n = 13) and age-matched healthy participants (n = 13) during low level muscle activation. Two sets of 10 responses were collected in the first session and a further 10 responses collected in a second session held 7 days later. Four MEP size measurements were made using 4, 6, 8, or all 10 of the MEPs collected. Intra- and inter-session reliability was examined using intraclass correlation coefficients (ICC) and typical percentage error. Results Intrasession ICC statistics using 6 or more MEPs were >0.85 in the stroke group but intersession values were all <0.5. Reliability was best when measuring parameters from individual MEPs rather than averaged responses. Conclusions Reliability of intrasession MEP size is excellent in the lower limb of patients with stroke using as few as 6 MEPs but intersession reliability is poor. Significance Comparing MEP size measures across two or more sessions is questionable in the lower limb of patients with stroke