No Time to Move: Motion, Painting and Temporal Experience

This paper is concerned with the senses in which paintings do and do not depict various temporal phenomena, such as motion, stasis and duration. I begin by explaining the popular – though not uncontroversial – assumption that depiction, as a pictorial form of representation, is a matter of an experiential resemblance between the pictorial representation and that which it is a depiction of. Given this assumption, I illustrate a tension between two plausible claims: that paintings do not depict motion in the sense that video recordings do, and that paintings do not merely depict objects but may depict those objects as engaged in various activities, such as moving. To resolve the tension, I demonstrate that we need to recognise an ambiguity in talk of the appearance of motion, and distinguish between the depiction of motion and the depiction of an object as an object that is moving. Armed with this distinction, I argue that there is an important sense in which paintings depict neither motion, duration, nor – perhaps more controversially – stasis

On the pathwise approximation of stochastic differential equations

We consider one-step methods for integrating stochastic differential equations and prove pathwise convergence using ideas from rough path theory. In contrast to alternative theories of pathwise convergence, no knowledge is required of convergence in pth mean and the analysis starts from a pathwise bound on the sum of the truncation errors. We show how the theory is applied to the Euler-Maruyama method with fixed and adaptive time-stepping strategies. The assumption on the truncation errors suggests an error-control strategy and we implement this as an adaptive time-stepping Euler-Maruyama method using bounded diffusions. We prove the adaptive method converges and show some computational experiments.Comment: 21 page

Well-posedness for a regularised inertial Dean-Kawasaki model for slender particles in several space dimensions

A stochastic PDE, describing mesoscopic fluctuations in systems of weakly interacting inertial particles of finite volume, is proposed and analysed in any finite dimension $d\in\mathbb{N}$. It is a regularised and inertial version of the Dean-Kawasaki model. A high-probability well-posedness theory for this model is developed. This theory improves significantly on the spatial scaling restrictions imposed in an earlier work of the same authors, which applied only to significantly larger particles in one dimension. The well-posedness theory now applies in $d$-dimensions when the particle-width $\epsilon$ is proportional to $N^{-1/\theta}$ for $\theta>2d$ and $N$ is the number of particles. This scaling is optimal in a certain Sobolev norm. Key tools of the analysis are fractional Sobolev spaces, sharp bounds on Bessel functions, separability of the regularisation in the $d$-spatial dimensions, and use of the Fa\`a di Bruno's formula.Comment: 28 pages, no figure

Laser pulse control of a Q-switched Nd:YVO₄ bounce geometry laser using a secondary cavity

Pulsed laser operation is desirable for a wide range of applications such as laser micromachining in industrial manufacturing and laser marking for product identification. In these cases it is beneficial to have flexibility in the parameters of the laser pulse to suit the specific application. This can include the ability to achieve a wide range of pulse repetition rates, with some applications requiring variation of laser pulse rate from high rate (multi-kHz) to low rate or even an off-state in a fast timescale. To generate ultrahigh pulse rates requires Q-switched lasers with ultrahigh gain, but problems can arise if the modulation element is insufficient to prevent laser action or hold-off lasing at low repetition rates. In these cases, lasing output can occur when it is not desired. In this work we present a novel method for pulse control in a high gain bounce amplifier Q-switched system by using a secondary cavity to clamp the gain and allow for clean single pulse operation from very high (800kHz) to very low (e.g.1kHz) repetition rates

Efficient conversion to radial polarization in the two-micron band using a continuously space-variant half-waveplate

We demonstrate efficient conversion of a linearly-polarized Gaussian beam to a radially-polarised doughnut beam in the two-micron band using a continuously space-variant half-waveplate created by femtosecond writing of subwavelength gratings. The low scattering loss (<0.07) of this device indicates that it would be suitable for use with high power lasers

Deanthropomorphising NLP: Can a Language Model Be Conscious?

This work is intended as a voice in the discussion over the recent claims that LaMDA, a pretrained language model based on the Transformer model architecture, is sentient. This claim, if confirmed, would have serious ramifications in the Natural Language Processing (NLP) community due to wide-spread use of similar models. However, here we take the position that such a language model cannot be sentient, or conscious, and that LaMDA in particular exhibits no advances over other similar models that would qualify it. We justify this by analysing the Transformer architecture through Integrated Information Theory. We see the claims of consciousness as part of a wider tendency to use anthropomorphic language in NLP reporting. Regardless of the veracity of the claims, we consider this an opportune moment to take stock of progress in language modelling and consider the ethical implications of the task. In order to make this work helpful for readers outside the NLP community, we also present the necessary background in language modelling