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X-WR-CALNAME:Particle Physics Theory Seminars
X-WR-CALDESC:Particle Physics Theory Seminars
X-PUBLISHED-TTL:PT12H
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VTIMEZONE
TZID:Europe/London
X-LIC-LOCATION:Europe/London
BEGIN:DAYLIGHT
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
DTSTART:19810329T010000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
TZNAME:BST
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TZOFFSETFROM:+0100
TZOFFSETTO:+0000
DTSTART:19961027T020000
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TZNAME:GMT
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BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79975@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20200206T092750
LAST-MODIFIED:20200520T161122
STATUS:CANCELLED
DTSTART;TZID=Europe/London:20200617T140000
DTEND;TZID=Europe/London:20200617T150000
SUMMARY:[CANCELLED] Alessandro Pilloni
DESCRIPTION:tba\n\nSpeaker:\n* Alessandro Pilloni (ECT* Trento)
LOCATION:Higgs Centre Seminar Room\, Room 4305\, JCMB
URL:https://www.ph.ed.ac.uk/events/2020/79975-alessandro-pilloni
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80056@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20200312T092240
LAST-MODIFIED:20200619T150814
STATUS:CANCELLED
DTSTART;TZID=Europe/London:20200624T140000
DTEND;TZID=Europe/London:20200624T150000
SUMMARY:[CANCELLED] Kai Yan
DESCRIPTION:tba\n\nSpeaker:\n* Dr Kai Yan (MPI Munich)
LOCATION:Higgs Centre Seminar Room\, Room 4305\, JCMB
URL:https://www.ph.ed.ac.uk/events/2020/80056-kai-yan
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79924@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20200113T143637
LAST-MODIFIED:20200520T154955
STATUS:CANCELLED
DTSTART;TZID=Europe/London:20200629T140000
DTEND;TZID=Europe/London:20200629T150000
SUMMARY:[CANCELLED] Making sense of the Nambu-Jona-Lasinio model via scale
invariance
DESCRIPTION:The status of the chiral-invariant Nambu-Jona-Lasinio (NJL) fo
ur-fermi model is quite equivocal. It serves as the paradigm for dynamical
symmetry breaking and yet it is not renormalizable. NJL only studied one
loop graphs with point vertices\, and needed to use an ultraviolet cutoff.
We propose to dress the point vertices with scale invariant vertices with
anomalous dimensions. We show that if the dimension of the $\\bar{\\psi}\
\psi$ fermion mass operator is reduced from a canonical three to a dynamic
al two\, the four fermion interaction becomes renormalizable to all orders
in the four-fermion coupling constant. Additionally\, we find that dynami
cal symmetry breaking then occurs with the fermion becoming massive\, and
we obtain a dynamical massless pseudoscalar Goldstone boson and a dynamica
l scalar Higgs boson. The Higgs boson mass is automatically of order the d
ynamical fermion mass\, with there thus being no hierarchy problem. The Hi
ggs boson automatically has a width\, and the width could serve as a diagn
ostic to distinguish a dynamical Higgs from an elementary one. We extend t
he scale invariance to local conformal invariance as then coupled to a gra
vity theory\, conformal gravity\, that is conformal too. With Bender and M
annheim having shown that conformal gravity is a ghost-free\, unitary theo
ry\, it can serve as a consistent theory of quantum gravity. We show that
all of the achievements of supersymmetry can be achieved by conformal symm
etry and conformal gravity instead\, with there then being no need for any
new particles at the LHC.\n\nSpeaker:\n* Prof Philip Mannheim (University
of Connecticut)
LOCATION:4325A\, James Clerk Maxwell Building\, King's Buildings
URL:https://www.ph.ed.ac.uk/events/2020/79924-making-sense-of-the-nambu-jo
na-lasinio-model-via-scale-invariance
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79954@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20200128T155201
LAST-MODIFIED:20200708T154521
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200708T140000
DTEND;TZID=Europe/London:20200708T150000
SUMMARY:Differential equations for one-loop string integrals
DESCRIPTION:This talk is dedicated to mathematical structures in the low-e
nergy expansion of \none-loop string amplitudes. I will review basics of s
tring perturbation theory and \ngive examples of connections with number t
heory from the integration over moduli \nof punctured worldsheet. At one l
oop\, the insertion of external states on the open- \nand closed-string wo
rldsheets requires integration over punctures on a cylinder \nboundary and
a torus\, respectively. Suitable bases of such integrals will be shown \n
to obey simple first-order differential equations in the modular parameter
of the \nsurface. These differential equations will be exploited to perfo
rm the integrals \norder by order in the inverse string tension\, similar
to modern strategies for \ndimensionally regulated Feynman integrals. Our
method manifests the appearance \nof iterated integrals over holomorphic E
isenstein series in the low-energy expansion. \nMoreover\, infinite famili
es of Laplace equations can be generated for the modular \nforms in closed
-string low-energy expansions.\n\nSpeaker:\n* Prof Oliver Schlotterer (Uni
versity of Uppsala)
LOCATION:https://eu.bbcollab.com/guest/9c7618378d804924a3a3ecd1521672a3
URL:https://www.ph.ed.ac.uk/events/2020/79954-differential-equations-for-o
ne-loop-string-integrals
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80723@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20200729T163335
LAST-MODIFIED:20200914T100227
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200902T140000
DTEND;TZID=Europe/London:20200902T150000
SUMMARY:Positivity Bounds: Building UV/IR Connections Using Scattering Amp
litudes
DESCRIPTION:The Effective Field Theory (EFT) framework has proven immensel
y successful in both particle physics and cosmology\, providing a means of
describing low-energy observations in the IR without reference to the (as
yet unknown) high-energy physics in the UV.\n But this decoupling of the
UV from the IR also presents a major obstacle to uncovering new fundamenta
l physics beyond the Standard Model and LambdaCDM - since it is not possib
le to probe the relevant energy scales directly\, it is difficult to go be
yond our low-energy effective descriptions.\n In this talk\, I will presen
t new developments in overcoming this obstacle.\n Certain fundamental prop
erties in the UV (such as causality\, locality and unitarity) leave charac
teristic imprints on the EFT scattering amplitude in the IR. These imprint
s\, known as “positivity bounds”\, can be used to bridge the gap betwe
en the UV and IR regimes.\n I will show how features of the UV can be infe
rred from our low-energy measurements\, and conversely how UV axioms can b
e used as priors to improve our IR parameter estimation of EFT coefficient
s.\n These “positivity” connections between the UV and IR regimes prov
ide us with a new way of analysing low-energy EFTs that will guide us towa
rds a better understanding of the new physics which lies beyond our curren
t models.\n\nSpeaker:\n* Dr Scott Melville (University of Cambridge)
LOCATION:https://ed-ac-uk.zoom.us/j/93887094261
URL:https://www.ph.ed.ac.uk/events/2020/80723-positivity-bounds-building-u
vir-connections-using-scattering-amplitudes
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80850@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20200902T095502
LAST-MODIFIED:20200917T093337
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200916T140000
DTEND;TZID=Europe/London:20200916T150000
SUMMARY:Massive Conformal Symmetry and Integrability for Feynman Integrals
DESCRIPTION:Since the rise of the AdS/CFT duality\, integrability has prov
en to be an important \ntool to advance our understanding of massless QFT.
\nIn this talk we demonstrate that integrability is also present in massi
ve QFT in D>2 \nspacetime dimensions. After reviewing the connection betwe
en AdS/CFT integrability \nand massless Feynman graphs\, we show that larg
e classes of massive Feynman integrals \nare highly constrained by an infi
nite dimensional Yangian extension of dual conformal \nsymmetry. When tran
slated to momentum space\, this leads to a novel massive generalization \n
of ordinary conformal symmetry. Finally\, we introduce a massive version o
f the so-called \nfishnet theory and argue that these features of massive
Feynman integrals can be understood \nas the integrability of planar scatt
ering amplitudes in this theory.\n\n\nSpeaker:\n* Florian Loebbert (Humbol
dt University Berlin)
LOCATION:https://ed-ac-uk.zoom.us/j/93564654489
URL:https://www.ph.ed.ac.uk/events/2020/80850-massive-conformal-symmetry-a
nd-integrability-for-feynman-integrals
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80952@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20201005T112014
LAST-MODIFIED:20201028T163402
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20201028T140000
DTEND;TZID=Europe/London:20201028T150000
SUMMARY:What are Black Holes?
DESCRIPTION:General Relativity conclusively establishes that when a suffic
iently large amount of matter is confined within a fixed volume\, \nthis m
atter will undergo gravitational collapse and form a singularity i.e. a po
int where General Relativity is broken. \nWhat happens to this collapsed o
bject? It is conventionally assumed that the Schwarzschild solution that i
s derived from General \nRelativity describes this space-time\, even thoug
h General Relativity cannot be used to describe the evolution of this coll
apsed \nobject once a singularity has formed. This assumption should be qu
estioned since the Schwarzschild geometry leads to the black \nhole inform
ation problem. Are there other possible final states? In this talk\, I wil
l present spherically symmetric solutions \nto Einstein’s equations whic
h are equivalent to canonical Schwarzschild black holes on the exterior bu
t with singular \n(i.e. Planck density) shells just outside their horizon\
, leading to a macroscopic singularity. These solutions are inspired by \n
the macroscopic singularities that need to exist at the inner horizons of
Reissner-Nordstrom and Kerr black holes to solve the \nCauchy horizon prob
lems of those geometries. While we can show the existence of such solution
s and analyze their stability\, \nwe cannot rigorously address their forma
tion - instead\, we suggest plausibility arguments for how “normal” bl
ack hole states may \nevolve into these solutions. We argue that the singu
lar nature of these solutions is critical for their formation from generic
\ninitial conditions\, distinguishing this class of solutions from black
hole mimickers such as gravastars and fuzzballs. \nWe also comment on poss
ible experimental tests in gravitational wave and electromagnetic observat
ories. \n\n\nMeeting Link:\n\nJoin Zoom Meeting\n\nhttps://ed-ac-uk.zoom.u
s/j/89108840817\n\nMeeting ID: 891 0884 0817\n\nPasscode: 8rJhS^gh\n\nJoin
by Skype for Business\n\nhttps://ed-ac-uk.zoom.us/skype/89108840817\n\nSp
eaker:\n* Prof Surjeet Rajendran (John Hopkins University)
LOCATION:Online - link below
URL:https://www.ph.ed.ac.uk/events/2020/80952-what-are-black-holes
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-81049@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20201023T155919
LAST-MODIFIED:20201104T153356
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20201104T140000
DTEND;TZID=Europe/London:20201104T150000
SUMMARY:An overview of Exceptional Field Theory with applications to the d
ouble copy for M-theory
DESCRIPTION:I will review an extension of general relativity called except
ional field theory that combines p-form gauge fields with the metric to fo
rm\n a single geometric quantity called the Generalised metric. As an appl
ication of this the Kerr-Schild Ansatz is for exceptional field theory\n a
nd applied to give a double copy type construction for the fields of M-the
ory. \n\nMeeting Link:\n\nJoin Zoom Meetinghttps://ed-ac-uk.zoom.us/j/840
24662450\n \n Meeting ID: 840 2466 2450\n Passcode: 9LJB1NrJ\n \n Join
by Skype for Businesshttps://ed-ac-uk.zoom.us/skype/84024662450\n\nSpeake
r:\n* David Berman (Queen Mary University of London)
LOCATION:Online - see below
URL:https://www.ph.ed.ac.uk/events/2020/81049-an-overview-of-exceptional-f
ield-theory-with-applications-to-the-double-copy-for-m-theory
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80899@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20200909T224851
LAST-MODIFIED:20201111T144419
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20201111T130000
DTEND;TZID=Europe/London:20201111T140000
SUMMARY:Stress-testing the Standard Model with lattice QCD
DESCRIPTION:I will show recent results from the HPQCD collaboration that a
llow stringent tests of the Standard Model \nin the physics of mesons cont
aining charm and bottom quarks. \nTuning quark masses and normalising curr
ent operators are critical to accuracy and I will discuss our recent \nimp
roved determination of the charm quark mass and current renormalisation fa
ctors for accurate matrix elements. \nI will also show results for meson d
ecay constants\, semileptonic form factors and B/Bs mixing amplitudes\, \n
all of which provide SM results for combining with experiment to determine
CKM elements or tests for new physics.\n\nMeeting Link:\n\nJoin Zoom Meet
ing\n\nhttps://ed-ac-uk.zoom.us/j/89359844439\n\nMeeting ID: 893 5984 4439
\n\nPasscode: 6ibhBzty\n\nJoin by Skype for Business\n\nhttps://ed-ac-uk.z
oom.us/skype/89359844439\n\nSpeaker:\n* Prof Christine Davies (University
of Glasgow)
LOCATION:Online - see below
URL:https://www.ph.ed.ac.uk/events/2020/80899-stress-testing-the-standard-
model-with-lattice-qcd
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80852@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20200902T095717
LAST-MODIFIED:20201118T152333
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20201118T140000
DTEND;TZID=Europe/London:20201118T150000
SUMMARY:Black hole perturbation theory and gravitational wave source model
ling
DESCRIPTION:Central to the gravitational wave detections by the current LI
GO-Virgo-KAGRA network of ground based detectors\, has been the underlying
analytical and numerical models of binary systems of compact objects (bla
ck holes\, neutron stars or combinations thereof). With future space based
detectors such as LISA\, new sources of gravitational waves will necessit
ate the need for new analytical models. One such source are extreme mass-r
atio inspirals\, where a ~10 solar mass compact object orbits a galactic-c
entre type massive black hole of ~10^6 solar masses.\n\nIn this talk I wil
l overview the role of black hole perturbation theory in describing these
objects using the gravitational self-force approach\, with an emphasis on
the relation to other analytical approaches to two-body dynamics in genera
l relativity. I will also discuss the use of analytic perturbation theory
to describe gravitational wave scattering in black hole spacetimes\, and t
he relation between this problem and scattering amplitudes for massive spi
nning particles in quantum field theory.\n\nMeeting Link:\n\nJoin Zoom Mee
ting\n\nhttps://ed-ac-uk.zoom.us/j/88619795004\n\nMeeting ID: 886 1979 500
4\n\nPasscode: 3f8u10&^\n\nJoin by Skype for Business\n\nhttps://ed-ac-uk.
zoom.us/skype/88619795004\n\nSpeaker:\n* Chris Kavanagh (Max Planck Instit
ute Potsdam)
LOCATION:Online - see below
URL:https://www.ph.ed.ac.uk/events/2020/80852-black-hole-perturbation-theo
ry-and-gravitational-wave-source-modelling
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80919@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20200918T214023
LAST-MODIFIED:20201202T195638
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20201202T170000
DTEND;TZID=Europe/London:20201202T180000
SUMMARY:From Scattering to the Dynamics of Black Holes and Fluids
DESCRIPTION:The study of scattering amplitudes has uncovered extraordina
ry dualities linking real-world particles like gravitons\, gluons\, and pi
ons. In this talk we describe recent progress exploring these structures i
n arenas less well-tread by particle physicists. First\, we discuss how
cutting edge ideas from amplitudes have been fused with classic tools fro
m effective field theory to derive now state-of-the-art results on the
orbital dynamics of binary black holes and neutron stars. Second\, we
show how the Navier-Stokes equation encodes scattering amplitudes of flu
id quanta which are also amenable to amplitudes analysis and exhibit a li
tany of familiar structures\, including soft theorems\, recursion\, and th
e double copy.\n\nMeeting Link:\n\nJoin Zoom Meeting\n https://ed-ac-uk.zo
om.us/j/81767029302\n\nMeeting ID: 817 6702 9302\n Passcode: 4YhHwdv&\n\nJ
oin by Skype for Business\n https://ed-ac-uk.zoom.us/skype/81767029302\n\n
Speaker:\n* Prof Clifford Cheung (Caltech)
LOCATION:Online - see below
URL:https://www.ph.ed.ac.uk/events/2020/80919-from-scattering-to-the-dynam
ics-of-black-holes-and-fluids
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-81104@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20201106T100901
LAST-MODIFIED:20201209T151328
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20201209T140000
DTEND;TZID=Europe/London:20201209T150000
SUMMARY:Multilevel Monte Carlo for quantum mechanics on a lattice
DESCRIPTION:Monte Carlo simulations of quantum field theories on a lattice
become increasingly expensive as the continuum limit is approached since
the cost per independent sample grows with a high power of the inverse la
ttice spacing. Simulations on fine lattices suffer from critical slowdown\
, the rapid growth of autocorrelations in the Markov chain with decreasin
g lattice spacing a. This causes a strong increase in the number of lattic
e configurations that have to be generated to obtain statistically signif
icant results. We discuss hierarchical sampling methods to tame this growt
h in autocorrelations\; combined with multilevel variance reduction techn
iques\, this significantly reduces the computational cost of simulations.\
n\nWe recently demonstrated the efficiency of this approach for two non-tr
ivial model systems in quantum mechanics in https://arxiv.org/abs/2008.030
90. This includes a topological oscillator\, which is badly affected by cr
itical slowdown due to freezing of the topological charge. On fine lattic
es our methods are several orders of magnitude faster than standard\, sing
le level sampling based on Hybrid Monte Carlo. For very high resolutions\
, multilevel Monte Carlo can be used to accelerate even the cluster algori
thm\, which is known to be highly efficient for the topological oscillator
. Performance is further improved through perturbative matching. This guar
antees efficient coupling of theories on the multilevel lattice hierarchy\
, which have a natural interpretation in terms of effective theories obta
ined by renormalisation group transformations.\n\nMeeting Link:\n\nJoin Zo
om Meeting\n https://ed-ac-uk.zoom.us/j/87693395173?pwd=N01UZSs4ZXNuQzVHNn
BOTDJkaTd6QT09\n\nMeeting ID: 876 9339 5173\n Passcode: 9ZSY+s0A\n\nJoin b
y Skype for Business\n https://ed-ac-uk.zoom.us/skype/87693395173\n\nSpeak
er:\n* Prof Eike Müller (University of Bath)
LOCATION:Online - see below
URL:https://www.ph.ed.ac.uk/events/2020/81104-multilevel-monte-carlo-for-q
uantum-mechanics-on-a-lattice
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80980@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20201009T130408
LAST-MODIFIED:20210120T221322
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20210120T170000
DTEND;TZID=Europe/London:20210120T180000
SUMMARY:Reweighting for Topology at High Temperatures
DESCRIPTION:Motivated by its importance for the cosmology of axions (a dar
k matter candidate)\, we examine how to compute the topological susceptibi
lity of QCD\n\nnonperturbatively on the lattice at temperatures well above
the QCD transition temperature. In this regime topological structures a
re rare in the QCD\n\nthermal ensemble\, and reweighting methods are neede
d to sample them effectively. We introduce the subject and show how to c
arry out such\n\nreweighted computations in lattice QCD.\n\nMeeting Link:\
n\nJoin Zoom Meeting\n\nhttps://ed-ac-uk.zoom.us/j/89371175701\n\nMeeting
ID: 893 7117 5701\n\nPasscode: ViCQ4wB8\n\nJoin by Skype for Business\n\nh
ttps://ed-ac-uk.zoom.us/skype/89371175701\n\nSpeaker:\n* Prof Guy Moore (T
echnical University of Darmstadt)
LOCATION:Online - see below
URL:https://www.ph.ed.ac.uk/events/2021/80980-reweighting-for-topology-at-
high-temperatures
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-81235@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20210118T231026
LAST-MODIFIED:20210210T183308
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20210210T170000
DTEND;TZID=Europe/London:20210210T180000
SUMMARY:Classical black hole scattering from a worldline QFT
DESCRIPTION:I will investigate the link between scalar-graviton S-matrix e
lements and expectation values of operators in a worldline QFT (WQFT)\, bo
th used to describe classical scattering of two black holes in the post-Mi
nkowskian (PM) expansion. The link provides a theoretical framework connec
ting recent state-of-the-art efforts to compute high-precision observables
relevant for gravitational wave astronomy. As a practical application I w
ill also show how to compute the far-field waveform produced from a black
hole scattering event\, to leading PM order.\n\nMeeting Link:\n\nTopic: Cl
assical black hole scattering from a worldline QFT\n Time: Feb 10\, 2021 0
4:45 PM London\n\nJoin Zoom Meeting\n https://ed-ac-uk.zoom.us/j/839670630
22\n\nMeeting ID: 839 6706 3022\n Passcode: hNGp1A8b\n\nJoin by Skype for
Business\n https://ed-ac-uk.zoom.us/skype/83967063022\n\nSpeaker:\n* Dr Gu
stav Mogull (Max Planck Institute for Gravitational Physics (Potsdam))
LOCATION:Online - see below
URL:https://www.ph.ed.ac.uk/events/2021/81235-classical-black-hole-scatter
ing-from-a-worldline-qft
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-81273@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20210129T124117
LAST-MODIFIED:20210217T220052
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20210217T170000
DTEND;TZID=Europe/London:20210217T180000
SUMMARY:Master integrals contributing to two loop planar ttgg amplitudes i
ncluding massive fermion loops
DESCRIPTION:In this talk I am going to discuss the analytic form for two l
oop amplitudes for ttgg. In particular\, I will discuss in detail the mast
er integrals with an internal massive loop\, and the special functions the
y evaluate to. The presence of elliptic curves in these master integrals m
ake the computations particularly interesting. I will also shed some light
on how to compute these master integrals numerically.\n\nMeeting Link:\n\
nhttps://ed-ac-uk.zoom.us/j/86232046447\n\nMeeting ID: 862 3204 6447\n\nPa
sscode: y4dBvDLq\n\nJoin by Skype for Business\n\nhttps://ed-ac-uk.zoom.us
/skype/86232046447\n\nSpeaker:\n* Dr Ekta Chaubey (University of Turin and
INFN Turin)
LOCATION:Online - details to follow
URL:https://www.ph.ed.ac.uk/events/2021/81273-master-integrals-contributin
g-to-two-loop-planar-ttgg-amplitudes-including-massive-fermion-loops
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-81232@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20210118T145740
LAST-MODIFIED:20210224T235315
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20210224T170000
DTEND;TZID=Europe/London:20210224T180000
SUMMARY:Amplitudes for Monopoles
DESCRIPTION: On-shell methods are particularly suited for exploring the s
cattering of electrically and magnetically charged objects\, for which the
re is no local and Lorentz invariant Lagrangian description. In this paper
we show how to construct a Lorentz-invariant S-matrix for the scattering
of electrically and magnetically charged particles. A key ingredient is a
revision of our fundamental understanding of multi-particle representation
s of the Poincaré group. Surprisingly\, the asymptotic states for electri
c-magnetic scattering transform with an additional little group phase\, as
sociated with pairs of electrically and magnetically charged particles. Th
e corresponding “pairwise helicity” is identified with the quantized
“cross product” of charges\, e1g2 − e2g1\, for every charge-monopole
pair\, and represents the extra angular momentum stored in the asymptotic
electromagnetic field. We define a new kind of pairwise spinor-helicity v
ariable\, which serves as an additional building block for electric-magnet
ic scattering amplitudes. We then construct the most general 3-point S-mat
rix elements\, as well as the full partial wave decomposition for the 2
→ 2 fermion-monopole S-matrix. In particular\, we derive the famous heli
city flip in the lowest partial wave as a simple consequence of a generali
zed spin-helicity selection rule\, as well as the full angular dependence
for the higher partial waves. Our construction provides a significant new
achievement for the on-shell program\, succeeding where the Lagrangian des
cription has so far failed.\n\nMeeting link:\n\nJoin Zoom Meeting\n https:
//ed-ac-uk.zoom.us/j/87284284556?pwd=L1ErN1pyUHAzSGJneC90RkVNK0VPZz09\n\nM
eeting ID: 872 8428 4556\n Passcode: nwyM9gbq\n\nJoin by Skype for Busines
s\n https://ed-ac-uk.zoom.us/skype/87284284556\n\nSpeaker:\n* Dr Ofri Tele
m (University of California\, Berkeley)
LOCATION:Online - details to follow
URL:https://www.ph.ed.ac.uk/events/2021/81232-amplitudes-for-monopoles
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-81260@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20210121T214710
LAST-MODIFIED:20210304T131049
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20210303T170000
DTEND;TZID=Europe/London:20210303T180000
SUMMARY:Classical dynamics from semiclassical scattering
DESCRIPTION:My talk will describe recent progress in the program to apply
modern tools for computing scattering amplitudes to problems in classical
general relativity. These include the calculation of the (potential contri
butions to the) conservative two-body Hamiltonian at the fourth order in
Newton’s constant\, G^4\, as well as the G^3 radiated energy in binary
black hole encounters and elliptical orbits. I will focus on two developm
ents that enabled these calculations. The first of these is an improved u
nderstanding of the connection between classical scattering amplitudes and
the semiclassical on-shell action. The other is the application of modern
loop integration methods\, such as canonical differential equations and r
everse unitarity\, to the kind of integrals relevant for the computation o
f classical quantities. Finally\, I will comment on certain universal feat
ures that can be observed by comparing the dynamics of black holes in clas
sical Einstein gravity and supergravity.\n\nMeeting link:\n\n\n https://ed
-ac-uk.zoom.us/j/82923886978?pwd=QVpsOVBuMHFvV3llZ1NCY2doRWxLZz09\n\nMeeti
ng ID: 829 2388 6978\n Passcode: C5gwYm7u\n\nJoin by Skype for Business\n
https://ed-ac-uk.zoom.us/skype/82923886978\n\nSpeaker:\n* Dr Julio Parra-M
artinez (California Institute of Technology)
LOCATION:Online - details below
URL:https://www.ph.ed.ac.uk/events/2021/81260-classical-dynamics-from-semi
classical-scattering
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-81262@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20210127T093549
LAST-MODIFIED:20210325T091936
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20210324T170000
DTEND;TZID=Europe/London:20210324T180000
SUMMARY:Full Angle Dependence of the Four-Loop Cusp Anomalous Dimension in
QED
DESCRIPTION:Angle-dependent cusp anomalous dimension governs the divergenc
es coming from soft gluon exchanges between massive particles. We compute
matter-dependent quartic Casimir component\, the first truly non-planar co
ntribution. Our result sheds new light on the infrared structure of gauge-
theory amplitudes at generic cusp angle. On the one hand\, it interpolates
between various physically interesting kinematic limits in both maximally
supersymmetric gauge theory (N=4 sYM)\, and QCD. On the other hand\, it c
onstitutes the first quantum correction beyond propagator-type diagrams in
the abelian theory. Obtaining an analytic four-loop prediction\, with exa
ct kinematic dependence\, is beyond the state of the art of most approache
s. To overcome various technical difficulties\, we developed an algorithm
for solving system of differential equations\, based only on partial knowl
edge of the canonical basis. We demonstrate its applicability and usefulne
ss to a large-scale problem\, and in particular\, systems of quasi-finite
integrals.\n\nMeeting link:\n\nhttps://ed-ac-uk.zoom.us/j/81331461714?pwd=
YjZnZjRuR0dTRWViSUZlcTBNOGx6UT09\n\nMeeting ID: 813 3146 1714\n Passcode:
iS5Nx9P2\n\nJoin by Skype for Business\n https://ed-ac-uk.zoom.us/skype/81
331461714\n\nSpeaker:\n* Dr Kai Yan (MPI Munich)
LOCATION:Online - details to follow
URL:https://www.ph.ed.ac.uk/events/2021/81262-full-angle-dependence-of-the
-four-loop-cusp-anomalous-dimension-in-qed
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-81531@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20210409T134406
LAST-MODIFIED:20210420T143013
STATUS:CANCELLED
DTSTART;TZID=Europe/London:20210421T140000
DTEND;TZID=Europe/London:20210421T150000
SUMMARY:[CANCELLED] Cwebs beyond three loops in multiparton amplitudes
DESCRIPTION:Correlators of Wilson line operators are known to exponentiate
in the non-abelian gauge theory and their logarithms can be arranged in t
erms of a collection of Feynman diagrams known as webs. Webs are a set of
diagrams that mix among themselves by a mixing matrix known. After reviewi
ng the algorithm to generate the mixing matrices and their properties\, I
will discuss some recent results\, a proposal for organizing webs at highe
r perturbative orders\, a new way of constructing the mixing matrices\, an
d the colour structures contributing to the soft anomalous dimension at th
e four-loop level.\n\nMeeting link\n\nhttps://ed-ac-uk.zoom.us/j/860335719
14\n\nMeeting ID: 860 3357 1914\n\nPasscode: WP41FL8z\n\nJoin by Skype for
Business\n\nhttps://ed-ac-uk.zoom.us/skype/86033571914\n\nSpeaker:\n* Sou
rav Pal (Indian Institute of Technology Hyderabad)
LOCATION:Online
URL:https://www.ph.ed.ac.uk/events/2021/81531-cwebs-beyond-three-loops-in-
multiparton-amplitudes
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-81312@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20210219T114205
LAST-MODIFIED:20210428T150837
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20210428T140000
DTEND;TZID=Europe/London:20210428T150000
SUMMARY:Compton amplitude and the nucleon structure functions on the latti
ce via the Feynman-Hellmann theorem
DESCRIPTION:In this talk\, I will be highlighting QCDSF/UKQCD Collaboratio
n's recent developments on computing the Compton amplitude in a lattice ap
proach. I briefly discuss how to access the Compton amplitude directly via
the second-order Feynman-Hellmann theorem and as an application\, present
a calculation of the nucleon Compton tensor across a range of photon mome
nta. This enables us to study the $Q^2$ dependence of the low moments of t
he nucleon structure functions in a lattice calculation for the first time
. I will also discuss possible further applications of this approach and p
resent some preliminary results.\n\nMeeting link:\n\nhttps://ed-ac-uk.zoom
.us/j/84412830952\n\nMeeting ID: 844 1283 0952\n\nPasscode: bX86vwaA\n\nJo
in by Skype for Business\n\nhttps://ed-ac-uk.zoom.us/skype/84412830952\n\n
Speaker:\n* Dr Kadir Utku Can (University of Adelaide)
LOCATION:Online
URL:https://www.ph.ed.ac.uk/events/2021/81312-compton-amplitude-and-the-nu
cleon-structure-functions-on-the-lattice-via-the-feynman-hellmann
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-81428@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20210317T132058
LAST-MODIFIED:20210505T154006
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20210505T140000
DTEND;TZID=Europe/London:20210505T150000
SUMMARY:Exploring large charge density systems with lattice QCD+QED
DESCRIPTION:Both the complexity of meson\, nucleon\, and nuclear systems t
hat can be studied using lattice QCD and the precision that can be achieve
d are steadily increasing. QED effects are being included in lattice calcu
lations of fundamental properties of the Standard Model such as meson and
baryon masses and contributions to g-2 of the muon targeting percent-level
or better precision. In systems of multiple charged particles\, QED effec
ts are challenging to include but can also become large and lead to nonper
turbative effects such as atomic binding. In this talk\, I will present la
ttice QCD+QED results for systems of up to 12 charged and neutral mesons t
hat explore the role of QED effects in multi-particle systems. I will also
present the construction of a non-relativistic effective field theory of
charged particles in a finite volume that can be used to constrain two- an
d three-meson interactions using these and future lattice QCD+QED results.
Finally\, I will discuss general lessons from these exploratory calculati
ons on the importance of nonperturbative Coulomb effects for future multi-
particle lattice QCD+QED calculations.\n\nMeeting link:\n\nJoin Zoom Meeti
ng\n\nhttps://ed-ac-uk.zoom.us/j/88455585610\n\nMeeting ID: 884 5558 5610\
n\nPasscode: Bgni6GHH\n\nJoin by Skype for Business\n\nhttps://ed-ac-uk.zo
om.us/skype/88455585610\n\nSpeaker:\n* Dr Michael Wagman (Fermilab)
LOCATION:Online - see below
URL:https://www.ph.ed.ac.uk/events/2021/81428-exploring-large-charge-densi
ty-systems-with-lattice-qcdqed
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-81459@www.ph.ed.ac.uk
DTSTAMP:20210614T025403
CREATED:20210322T100704
LAST-MODIFIED:20210512T233839
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20210512T140000
DTEND;TZID=Europe/London:20210512T150000
SUMMARY:Symmetry meets AI
DESCRIPTION:Artificial Intelligence\, especially its branch of Deep Learni
ng\, is a disruptive technology whose implications we are just starting to
fathom. Due to its impressive successes\, AI is somehow regarded as a mag
ical blackbox\, able to surpass human ability in an inexplicable way. We\,
theoretical physicists\, do not like blackboxes and enjoy breaking things
. So in this talk I am going to start breaking one of these boxes and watc
h an AI learn the presence of symmetries when no information on symmetry w
as provided. It isn't magic\, but it is the AI doing its best to perform a
task and finding the smartest route to succes. Once we have learned the i
nner workings of the AI\, we are going to use it to develop an algorithm w
hich inspects artistic works and assigns a degree of symmetry to them. Thi
s is one step towards a much broader aim of understanding the inner workin
gs of AI\, like developing new ways of learning or controlling for the pre
sence of unethical biases.\n\nMeeting link:\n\nhttps://ed-ac-uk.zoom.us/j/
84609346493\n\nMeeting ID: 846 0934 6493\n\nPasscode: 2Bk6NQ1c\n\nJoin by
Skype for Business\n\nhttps://ed-ac-uk.zoom.us/skype/84609346493\n\nSpeake
r:\n* Veronica Sanz (University of Sussex)
LOCATION:Online - details below
URL:https://www.ph.ed.ac.uk/events/2021/81459-symmetry-meets-ai
END:VEVENT
END:VCALENDAR