Policing the Windrush Generation

Executive Summary West Indians were the first group of non-white immigrants to settle in Britain in large numbers after World War Two. Many arrived with a perception of the 'mother' country that was naïve and left them ill-prepared to deal with the hostility and resentment of the host community. The police service, to which immigrants turned for help when confronted with problems associated with racial prejudice, was drawn exclusively from the host community, sharing its attitudes and prejudices. It was during the early years of large-scale immigration that attitudes and misconceptions developed between police and West Indian immigrants that resulted in mutual stereotyping. Racial prejudice, and the police service's reluctance to see beyond its own priorities to prevent and detect crime, led the Metropolitan Police to reject the West Indian community's offer to assist with police training in community relations at the very time when difficulties between the two sides were becoming apparent. Although the Metropolitan Police began racial-awareness training for recruits in 1964, the training was largely tokenistic. Following the Scarman Report of 1981, community and race-relations training for the police was revamped in 1984, but claims of lack of commitment and support at all levels have persisted. Current community and race-relations training for Metropolitan Police staff ignores the historic background of difficulties in relations with the black community. As such, new recruits lack an in-depth understanding of the way in which negative feelings on the part of the police towards West Indians in the early years of large-scale immigration fed developing perceptions of the police as being oppressive and racist

Local spin operators for fermion simulations

Digital quantum simulation of fermionic systems is important in the context of chemistry and physics. Simulating fermionic models on general purpose quantum computers requires imposing a fermionic algebra on spins. The previously studied Jordan-Wigner and Bravyi-Kitaev transformations are two techniques for accomplishing this task. Here we re-examine an auxiliary fermion construction which maps fermionic operators to local operators on spins. The local simulation is performed by relaxing the requirement that the number of spins should match the number of fermionic modes. Instead, auxiliary modes are introduced to enable non-consecutive fermionic couplings to be simulated with constant low-rank tensor products on spins. We connect the auxiliary fermion construction to other topological models and give examples of the construction

The computational complexity of density functional theory

Density functional theory is a successful branch of numerical simulations of quantum systems. While the foundations are rigorously defined, the universal functional must be approximated resulting in a `semi'-ab initio approach. The search for improved functionals has resulted in hundreds of functionals and remains an active research area. This chapter is concerned with understanding fundamental limitations of any algorithmic approach to approximating the universal functional. The results based on Hamiltonian complexity presented here are largely based on \cite{Schuch09}. In this chapter, we explain the computational complexity of DFT and any other approach to solving electronic structure Hamiltonians. The proof relies on perturbative gadgets widely used in Hamiltonian complexity and we provide an introduction to these techniques using the Schrieffer-Wolff method. Since the difficulty of this problem has been well appreciated before this formalization, practitioners have turned to a host approximate Hamiltonians. By extending the results of \cite{Schuch09}, we show in DFT, although the introduction of an approximate potential leads to a non-interacting Hamiltonian, it remains, in the worst case, an NP-complete problem.Comment: Contributed chapter to "Many-Electron Approaches in Physics, Chemistry and Mathematics: A Multidisciplinary View