Quantum fidelity approach to the ground state properties of the 1D ANNNI model in a transverse field

In this work we analyze the ground-state properties of the $s=1/2$ one-dimensional ANNNI model in a transverse field using the quantum fidelity approach. We numerically determined the fidelity susceptibility as a function of the transverse field $B_x$ and the strength of the next-nearest-neighbor interaction $J_2$, for systems of up to 24 spins. We also examine the ground-state vector with respect to the spatial ordering of the spins. The ground-state phase diagram shows ferromagnetic, paramagnetic, floating, $\Braket{2,2}$ phases, and we predict an infinite number of modulated phases in the thermodynamic limit ($L \rightarrow \infty$). The transition lines separating the modulated phases seem to be of second-order, whereas the line between the floating and the $\Braket{2,2}$ phases is possibly of first-order.Comment: 10 pages, 20 figure

Breeding futures: masculinity and the ethics of CUMmunion in Treasure Island Media's Viral Loads

This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this record.In a recent interview, pornographer Paul Morris claimed his studio, Treasure Island Media (TIM), is a ‘laboratory exploring the vital sexual symbiosis of human and viral DNA.’ Departing from that claim, I examine his porn text Viral Loads to explore its implications for thinking future-orientated masculinities and community formations. I claim that Viral Loads forces us to rethink modern ideals of individual autonomy and bodily integrity and alludes to alternative community formations enacted not by holding something in common but by relentlessly giving and exchanging foreign matter. By depicting ‘loads’ circulating between bodies posited as interfaces, Viral Loads gives us a porous and impure form of masculinity. In so doing, it breeds a queer future in which community ethics becomes an ethics of cummunion, a cummoning with strangers that is offered as an alternative to the politics of self and other

Acting in the Face of Strangers: a Response to Jane Bennett’s Political Ecology

Accepted for publication in: A Feeling For Things: Conversations On and Around the Work of Jane Bennett, edited by Lisa Baraitser, Michael O’Rourke, punctum books. Publication abandone

Phase transitions in the two-dimensional super-antiferromagnetic Ising model with next-nearest-neighbor interactions

We use Monte Carlo and Transfer Matrix methods in combination with extrapolation schemes to determine the phase diagram of the 2D super-antiferromagnetic (SAF) Ising model with next-nearest-neighbor (nnn) interactions in a magnetic field. The interactions between nearest-neighbor (nn) spins are ferromagnetic along x, and antiferromagnetic along y. We find that for sufficiently low temperatures and fields, there exists a region limited by a critical line of 2nd-order transitions separating a SAF phase from a magnetically induced paramagnetic phase. We did not find any region with either first-order transition or with re-entrant behavior. The nnn couplings produce either an expansion or a contraction of the SAF phase. Expansion occurs when the interactions are antiferromagnetic, and contraction when they are ferromagnetic. There is a critical ratio R_c = 1/2 between nnn- and nn-couplings, beyond which the SAF phase no longer exists.Comment: 12 pages, 10 figure

Comment on Long-Time Dynamics via Direct Summation of Infinite Continued Fractions

A Comment on the Letter by Z.-X. Cai et al., Phys. Rev. Lett. 68, 1637 (1992)

Quantum phase transitions in the transverse one-dimensional Ising model with four-spin interactions

In this work we investigate the quantum phase transitions at zero temperature of the one-dimensional transverse Ising model with an extra term containing four-spin interactions. The competition between the energy couplings of the model leads to an interesting zero-temperature phase diagram. We use a modified Lanczos method to determine the ground state and the first excited state energies of the system, with sizes of up to 20 spins. We apply finite size scaling to the energy gap to obtain the boundary region where ferromagnetic to paramagnetic transition takes place. We also find the critical exponent associated with the correlation length. We find a degenerate ⟨3,1⟩ phase region. The first-order transition boundary between this phase and the paramagnetic phase is determined by analyzing the behavior of the transverse spin susceptibility as the system moves from one region to the other