Phase diagram and quasiparticle properties of the Hubbard model within cluster two-site DMFT

We present a cluster dynamical mean-field treatment of the Hubbard model on a square lattice to study the evolution of magnetism and quasiparticle properties as the electron filling and interaction strength are varied. Our approach for solving the dynamical mean-field equations is an extension of Potthoff's "two-site" method [Phys. Rev. B. 64, 165114 (2001)] where the self-consistent bath is represented by a highly restricted set of states. As well as the expected antiferromagnetism close to half filling, we observe distortions of the Fermi surface. The proximity of a van Hove point and the incipient antiferromagnetism lead to the evolution from an electron-like Fermi surface away from the Mott transition, to a hole-like one near half-filling. Our results also show a gap opening anisotropically around the Fermi surface close to the Mott transition (reminiscent of the pseudogap phenomenon seen in the cuprate high-Tc superconductors). This leaves Fermi arcs which are closed into pockets by lines with very small quasiparticle residue.Comment: 10 pages, 8 figures, latex (revtex4

Small-angle scattering in a marginal Fermi-liquid

We study the magnetotransport properties of a model of small-angle scattering in a marginal Fermi liquid. Such a model has been proposed by Varma and Abrahams [Phys. Rev. Lett. 86, 4652 (2001)] to account for the anomalous temperature dependence of in-plane magnetotransport properties of the high-Tc cuprates. We study the resistivity, Hall angle and magnetoresistance using both analytical and numerical techniques. We find that small-angle scattering only generates a new temperature dependence for the Hall angle near particle-hole symmetric Fermi surfaces where the conventional Hall term vanishes. The magnetoresistance always shows Kohler's rule behavior.Comment: 4 pages, 3 figures, Revtex

'Mad' Edwin Withers and the Struggle for Fair Trial Rights in NSW

Since the 1980s, a number of fair trial rights and civil liberties have been eroded in Australia, particularly in respect to summary justice and police powers. This article traces the 'bottom-up' origins of some of those rights and liberties in colonial New South Wales. It focuses on the activist Edwin Withers and his interactions with the Parramatta magistracy in the mid 1840s. The Withers example enables us to see how some fair trial rights and civil liberties resulted from community-based social activism, which relied upon the legislature and higher court authority to become law. The importance of these rights - for example, the right to counsel, the right to a fair and impartial tribunal and protection against arbitrary detention - is demonstrated by the very fact that they issued from the working and middle classes and are implicated within wider class relationships involving residents of a local community. Using archival research and qualitative analysis, this article has important implications for Australian legal history in relation to the adoption of the Jervis Acts 1848 (UK), some of the first summary procedure legislation enacted within colonial NSW. The article demonstrates how the fair trial rights campaign at Parramatta resulted in amendment to the adopted Acts in the colony

Silence Matters: A survey of the right to silence in the summary jurisdiction of New South Wales

© The Author(s) 2019. There is a scant existing literature on the relationship between the right to silence and its effect on convictions in Australia and comparable jurisdictions. Existing research has downplayed its significance in the face of various ‘law and order’ interventions seeking to limit its operation. This study is one of the largest of its kind, surveying over 1,000 charges to empirically assess the frequency of use and the effects of silence rights (the right to silence, privilege against self-incrimination and burden of proof) on conviction, in relation to a particular set of charges laid against a specific group of marginalised defendants in the Local Court summary jurisdiction of NSW. Adding to the existing literature, this study shows empirically how silence rights operate within an Australian summary jurisdiction for a specific group of criminal defendants who are significantly socially marginalised. In the process, it demonstrates that the use of silence rights is significant for this group, mostly in non-regulatory criminal matters. In this respect, silence rights can be understood to correlate with rates of conviction, mitigation of criminal sentencing and the practice of charge-bargaining

The impacts of vehicle disturbance on NSW saltmarsh: implications for rehabilitation

Coastal saltmarshes are recognised globally as important ecological communities that are increasingly under threat. The use of off-road vehicles in saltmarsh environments has been identified as a very serious and rapidly escalating threat to these ecosystems. Despite this, vehicle disturbance within saltmarsh ecosystems has not been widely studied, particularly in the Australian context. Further understanding of the nature of this threat is required to provide knowledge for potential rehabilitation strategies. This study aimed to assess the impacts of vehicles on saltmarsh, at two locations on the South Coast of NSW, Australia. I adopted a multi-disciplinary approach to assess the impacts of vehicles on a range of biotic and abiotic variables. Biotic variables included abundance and composition of both the standing vegetation and the soil seed bank. The soil seed bank was assessed via a seedling emergence study, whereby soil samples were placed in greenhouses under conditions favourable for germination, and counted and identified as they emerged. Abiotic variables assessed included physical soil properties, chemical soil properties, micro-topography and hydrology. Physical and chemical soil properties were examined using a combination of field and laboratory techniques. The spatial extent of vehicle damage was determined, as well as the impacts of vehicles on micro-topography and hydrology using Geographic Information Systems (GIS). This study demonstrated that vehicles adversely impact saltmarsh ecosystems in a number of ways. Vegetation cover was on average 90% lower within vehicle tracks and the average number of plant species was halved. Changes to vegetation species composition were associated with vehicle damage, with impacted areas more likely to comprise species characteristic of the lower saltmarsh zone. The soil seed bank was adversely affected by vehicle disturbance, with an 80% reduction in average seed density within the soil of tracks. As the soil seed bank plays a vital role in vegetation recovery post-disturbance, reduced seed densities within the soil of vehicle tracks were considered major barriers to natural regeneration of damaged areas. Vehicle damage was also associated with changes to the local abiotic environment. Increased soil compaction was identified as a major impact of vehicle disturbance. Overall soil quality was found to be reduced in areas of disturbance, with lower levels of soil organic matter within vehicle damaged areas. Vehicle tracks were also associated with localised depressions in the marsh surface and thus, altered hydrological conditions. These factors were considered to have significant influence on ecological function of the saltmarsh and were identified as major factors limiting regeneration in vehicle damaged areas. Investigation of the impacts of vehicles on South Coast saltmarsh sites revealed that unassisted regeneration may not always be possible, and more active rehabilitation measures may be required in response to vehicle disturbance

Undoing a model system: A new federal custody notification service

© The Author(s) 2018. The Custody Notification Service is a legislative scheme to prevent Aboriginal deaths in custody. This article discusses proposed changes to the federal Custody Notification Service, that were before the federal Parliament in late 2017. It argues that the changes are inadequate, when compared with Custody Notification Service models in other Australian jurisdictions, primarily because the laws deprive Aboriginal people of important fair trial and custody rights. This article concludes by listing a range of legislative solutions proposed by Aboriginal organisations and legal representatives

Regulating Executive Salaries and Reducing Pay Disparities: Is pay disclosure the answer?

In 2017 it was reported that Ahmed Fahour, CEO of Australia Post – a publicly owned company – earned AUD$10.8 million in a single year. In 2015, he was paid 119 times the annual salary of the average Australia Post employee ($47,000 per annum). Fahour presided over the organisation's greatest decline in company turnover, accompanied by large-scale retrenchments of low-paid workers (Evershed, 2017). Yet as extravagant as Fahour’s pay appears, it is far from the largest executive remuneration packages paid to CEOs in Australia. In recent years, some have surpassed $30 million per annum. In the United States (US), CEO pay can be 300 times that of the average wage within the company (Mishel and Davis, 2015). Even after a slight ‘correction’ in CEO pay, which dipped in Australia during the Global Financial Crisis from an average of$5.5 million per annum to $4.7 million, David Richardson of The Australia Institute has recently found that CEO pay is on the rise again, averaging$5.2 million last financial year (Patty, 2018; Richardson, 2018)