I list a few examples of interesting topics in UX: Flow, Presence and the Effects of Realism. Pleas enote that these are no longer very active areas of research for me but suitably self motivated students may apply.

Flow in Computer Games

How would we characterize a really engaging or enjoyable game? We already have a reasonable approach to measuring that sort of thing in Virtual Environments (see Presence below). A strict definition of Presence however attempts to ignore the contents of the experience: which is precisely what is central in a game! Building on the idea of an Optimal Experience or Flow Experience by Csíkszentmihályi we want to explore what a measure of "Presence + Content" would be in games.
We look in the first instance at the genre of Sandbox Games — games that have open-ended worlds, through which there is no one single, correct pathway. Sandbox games are known for their status as contexts for creative player expression, with multiple solution paths (their quality is judged according to their ability to deliver such an experience).

Presence and Virtual Environment Applications

Collaborative Virtual Environments (CVEs) provide new possibilities for communication and collaboration, with a lot of potential and enhancements for the way we work and exchange information. For such systems to be successful they must provide participants with a high sense of presence; giving them a sense of ‘being there’ in the place specified by the virtual environment rather than just seeing images in the lab.
We are interested in the extent that virtual environments can elicit real emotional responses from participants. We believe that this aim makes for an interesting “hard problem” on which to focus our ambitions. In this work you are likely to build a CVE and then evaluate its effectiveness. You may also try to advance the theory of Presence in terms of underlying causes or in terms of measurement techniques.
A particular application of interest is the use of VEs for storytelling.

Use of Realism

A reflection on the use of realism in games and virtual reality. This is particularly relevant because our work focuses on the role of content and on low-cost solutions. Both aspects call into question the need for perceptual realism as the primary focus of a Virtual Reality experience. We will consider the degree to which notions of realism evolve (so that what was perceived as realistic at one time becomes crude and artificial later on) and the extent to which an experience is labelled realistic depends on the extent of user presence independent of objective measures of perceptual fidelity to reality.