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Dear All,</div>
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<span style="line-height: 1.38;">We have a seminar this week, whose details are provided below - </span></div>
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<b>Speaker:</b> <b>Qi-Xin Xie</b> (University of Nottingham) </div>
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<b>Seminar date:</b> <b>3rd Feb, Tuesday, 1 pm </b>UK time</div>
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<b>Venue:</b> Seminar Room <b>A 113 (Cripps North Building, CAPT)</b></div>
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<b>Title: Quantum fields in boson star spacetime</b></div>
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<b>Abstract</b>: </div>
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Boson stars have been extensively studied in classical gravity, but their quantum properties remain comparatively unexplored. We compute the quantum scalar fields and stress tensor in boson star spacetimes within the framework of semiclassical gravity. Divergences
are regularized using Pauli-Villars fields, and accurate numerical results are obtained through spectral methods. Employing coherent states enables a direct comparison between the classical part of the stress tensor and the quantum fluctuation. Our results
indicate that strong spacetime curvature is the primary source of large quantum effects. The renormalized quantum energy density is mostly positive but the radial pressure is negative, suggesting that classical boson star solutions require modification once
quantum effects are included. Moreover, in regimes of large curvature, the quantum fluctuations can constitute a significant fraction of the total stress tensor. The methods developed here can be generalized to other compact objects and used to study their
response to quantum corrections.</div>
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<b>Link to join:</b></div>
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<span style="color: black;"> </span><span style="color: rgb(5, 99, 193);"><u><a style="color: rgb(5, 99, 193); margin: 0px;" data-auth="NotApplicable" data-linkindex="0" title="https://teams.microsoft.com/l/meetup-join/19%3ameeting_OGM3OTk5NzQtZWEwZS00ZmUyLTk3MGUtZjFhY2M5OTU2MjI1%40thread.v2/0?context=%7b%22Tid%22%3a%2267bda7ee-fd80-41ef-ac91-358418290a1e%22%2c%22Oid%22%3a%22f3250584-4b5f-48fa-a897-08e77f2246b7%22%7d" class="OWAAutoLink" id="OWAf8f9b56c-ac6e-1f8a-04e7-cfe418922906" href="https://teams.microsoft.com/l/meetup-join/19%3ameeting_OGM3OTk5NzQtZWEwZS00ZmUyLTk3MGUtZjFhY2M5OTU2MjI1%40thread.v2/0?context=%7b%22Tid%22%3a%2267bda7ee-fd80-41ef-ac91-358418290a1e%22%2c%22Oid%22%3a%22f3250584-4b5f-48fa-a897-08e77f2246b7%22%7d">https://teams.microsoft.com/l/meetup-join/19%3ameeting_OGM3OTk5NzQtZWEwZS00ZmUyLTk3MGUtZjFhY2M5OTU2MjI1%40thread.v2/0?context=%7b%22Tid%22%3a%2267bda7ee-fd80-41ef-ac91-358418290a1e%22%2c%22Oid%22%3a%22f3250584-4b5f-48fa-a897-08e77f2246b7%22%7d</a></u></span></div>
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<b><i>List of the following five upcoming seminars (not everyone has given us a title yet):</i></b></div>
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10-Feb <b>Valeriya Korol</b> (<span style="font-weight: 500;">Max Planck Inst.</span>, Garching, Germany) (ONLINE) Galactic Astrophysics with LISA</div>
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17-Feb <b>David Seery</b> (Sussex) </div>
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24-Feb <b>George Efstathiou</b> (Cambridge) </div>
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3-Mar <b>Jon Butterworth</b> (UCL) Future-proofing measurements to probe the energy frontier</div>
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10-Mar <b>Basudeb Dasgupta</b> (<span style="font-weight: 500;">Tata Inst., Mumbai, India</span>) (ONLINE) Probing Dark Matter with Gravitational Waves from Mergers</div>
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<b>Finally the full list can be found here:</b></div>
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<a style="margin: 0px;" data-auth="NotApplicable" data-linkindex="1" title="https://www.nottingham.ac.uk/physics/research/particle-cosmology/seminars/seminars.aspx" class="OWAAutoLink" id="OWA5c3900fc-4bdf-ac9a-9742-6e5939b2a471" href="https://www.nottingham.ac.uk/physics/research/particle-cosmology/seminars/seminars.aspx">https://www.nottingham.ac.uk/physics/research/particle-cosmology/seminars/seminars.aspx</a></div>
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Please let us know if you would like to chat with the speaker and we will arrange for that. </div>
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Best wishes,</div>
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Ed and Qi-Xin</div>
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