Non-Fermi Liquid behavior at the Orbital Ordering Quantum Critical Point in the Two-Orbital Model

The critical behavior of a two-orbital model with degenerate $d_{xz}$ and $d_{yz}$ orbitals is investigated by multidimensional bosonization. We find that the corresponding bosonic theory has an overdamped collective mode with dynamical exponent $z=3$, which appears to be a general feature of a two-orbital model and becomes the dominant fluctuation in the vicinity of the orbital-ordering quantum critical point. Since the very existence of this $z=3$ overdamped collective mode induces non-Fermi liquid behavior near the quantum critical point, we conclude that a two-orbital model generally has a sizable area in the phase diagram showing non-Fermi liquid behavior. Furthermore, we show that the bosonic theory resembles the continuous model near the d-wave Pomeranchuk instability, suggesting that orbital order in a two-orbital model is identical to nematic order in a continuous model. Our results can be applied to systems with degenerate $d_{xz}$ and $d_{yz}$ orbitals such as iron-based superconductors and bilayer strontium ruthenates Sr$_3$Ru$_2$O$_7$.Comment: 5 pages, 2 figure

Using Bibliodrama in Hong Kong to Address Mental Illness

During the pandemic in recent years, utilising expressive arts as psychological intervention has been discussed in Hong Kong. Nevertheless, introducing expressive arts in local social work and medical settings is challenging due to the human service professionals lacking the understanding of this new method. In religious organizations, which are common in the Hong Kong social welfare system, there may be more obstacles. The literature review firstly defines religion and spirituality, and their importance for people with serious mental illness then discusses the effectiveness of psychodrama and Bibliodrama for the targeted population. A six-session workshop was delivered, containing three-sessions of expressive arts training, two-sessions of Bibliodrama, and one session of sharing. The results showed a group of people with diverse cognitive abilities understood the text of the Bible, through action based drama activities. Role-empathizing, processing of text interpretations, and engaging with group conflicts were experienced. The core features of Bibliodrama, modifications made for the group with serious mental illness, and observed cultural concerns are highlighted and discussed. Lastly, limitations are stated with the researcher’s personal reflection

From invisible to visible : representations and self-representaions of Hakka women In Hong Kong, 1900s-present

What we perceive as the essential characteristics of Hakka women today are in fact historically constructed and utilized for various purposes by different agents, including Western missionaries, Hakka elites, museum curators and heritage preservationists. This long historical process has made the Hakka women increasingly visible in the public scene. Some scholars argue that it was the men who attempted to manipulate the representations of Hakka women to justify their exploitation of women. As Hung Hsin-lan and Helen Siu have reminded us, the study of Hakka women should be liberated from the lens of exploitation and victimhood and we should position Hakka women in relation to Hakka men to achieve a more balanced analysis. In addition to examining the historical writings about Hakka and Hakka women since the nineteenth century, this thesis focuses on Hong Kong, and also considers the topic through a gender lens, to evaluate the roles that Hakka women have played in the museums and in the surging wave of cultural preservation. The aim of this thesis is to explain how Hakka women have been represented in various media and what has constituted our current perceptions and (mis)understandings toward Hakka women. While the Hakka women have been singled out to represent Hakka culture and have enjoyed the opportunity to create their self-representations, where have the Hakka men gone? What does it mean by a ‘Hakka’ when the Hakka identity is historically constructed in the first place? The present research adopts a combined historical and anthropological approach to rethink the images of Hakka women and review the interactions between the representations and self-representation of Hakka women in the displays and heritage preservation, which point to the broader themes of the interplays between colonialism and ethnicities, the politics of display, gender studies on exhibition and cultural heritage, and the impacts of global cultural trends on local culture formulation

Episodic-like Memory in Dogs: Solving What-Where-When Tasks

Episodic memory is a unique, personal memory that contains what happened, where it happened, and when it happened. Although episodic-like memory (ELM) in non-human animals has been shown using ­­what-where-when (WWW) memory paradigms, it has not previously been shown in dogs. Dogs are an excellent candidate for developing translational models of neurodegenerative disorders related to episodic memory, including Alzheimer’s disease. Dogs were tested on experiments that involved spatially and temporally unique odour sequences. Dogs were tested to see if they remembered the odours, their locations, and their time of presentation by choosing the earlier-exposed odour at the test. Findings suggest that dogs can encode ELM, can flexibly use WWW memory on unpredictable tests, and can solve a similar what-where task without odours. My study reveals the usefulness of utilizing olfactory cues to study ELM, and its potential usefulness in examining other aspects of cognition in dogs

KLZ: A Prototype X Protocol Compression System

One of the most commonly used graphics protocol is the X Protocol, enabling programs to display graphics images. When running the X Protocol over the network, a lot of structured data (messages with fields) need to be transmitted. Delays can be detected by human users when connected through a low-bandwidth network. The solution is to compress the X protocol. XRemote, a network version of the X Protocol, uses Dictionary-based compression. In XRemote, strings are recorded in the dictionary. When a string repeats, its index in the dictionary is transmitted. Higher Bandwidth X (HBX) uses statistical modeling techniques instead. A context model, which depends on the nature of the field in a particular type of message and the frequencies of the values of the field, is associated with each field. XRemote is much faster than HBX, but HBX achieves better compression than XRemote. The KLZ system is developed to take advantage of our knowledge about the fields in the XMotionNotify packet (what X sends when the mouse moves) and fast Dictionary (LZW) compression. In essence, KLZ reorders and rewrites fields in the XMotionNotify packet so that the fields will be more easily compressed by the fast LZ coder. My experiments show that KLZ compresses this packet nearly as well as HBX, and 5 times better than pure LZ. KLZ is slightly faster than pure LZ, and and 10 times faster than HBX. Since many modems already implement LZ compression, KLZ could also be used to reorder data before passing them to the modem with LZ compression for transmission. This reordering would lead to vastly improved compression almost for free

Pomeranchuk Instability in a non-Fermi Liquid from Holography

The Pomeranchuk instability, in which an isotropic Fermi surface distorts and becomes anisotropic due to strong interactions, is a possible mechanism for the growing number of experimental systems which display transport properties that differ along the $x$ and $y$ axes. We show here that the gauge-gravity duality can be used to describe such an instability in fermionic systems. Our holographic model consists of fermions in a background which describes the causal propagation of a massive neutral spin-two field in an asymptotically AdS spacetime. The Fermi surfaces in the boundary theory distort spontaneously and become anisotropic once the neutral massive spin-two field develops a normalizable mode in the bulk. Analysis of the fermionic correlators reveals that the low-lying fermionic excitations are non-Fermi liquid-like both before and after the Fermi surface shape distortion. Further, the spectral weight along the Fermi surface is angularly dependent and can be made to vanish along certain directions.Comment: Updated version to appear in PRD. New version has WKB analysis of spectral intensity in ordered phas

Methods for assessing the effects of spatial luminance patterns on perceived qualities of concert lighting

This paper presents experimental approaches for evaluating concert lighting from the viewpoints of audience members and performers in Cambridge King's College Chapel. We develop image zoning and abstraction techniques to quantify and interpret photometric data acquired under four different electric lighting conditions. Assessed by 78 participants, these lighting scenarios are compared across six different viewing positions using a set of structured questionnaires. Ordered logistic regression modelling shows that the ratios and functions describing uniformity, brightness and light patterns are common explanatory variables for predicting perceived visual clarity, visual uniformity, brightness and spatial intimacy. Uniformity-related attributes are observed to be among the strongest variables for all these perceived qualities, except for visual clarity, which is better explained by acuity-related measures. These experimental results confirm the applicability of our approaches, highlighting the importance of combining multiple methods and integrating complex architectural situations into the process of understanding luminous appearance. Cambridge Trus