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BEGIN:VEVENT
SUMMARY:Barton Zwiebach (MIT)
DTSTART:20211029T130000Z
DTEND:20211029T143000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/1
DESCRIPTION:by Barton Zwiebach (MIT) as part of SFT@Cloud Journal Club\n\n
Abstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Carlo Maccaferri (INFN\, Turin)
DTSTART:20211112T140000Z
DTEND:20211112T153000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/2
DESCRIPTION:by Carlo Maccaferri (INFN\, Turin) as part of SFT@Cloud Journa
l Club\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nathan Berkovits (ICTP-SAIFR)
DTSTART:20211203T140000Z
DTEND:20211203T153000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/3
DESCRIPTION:Title: Applications of the N=1 d=4 spacetime-supersymmetric versio
n of open superstring field theory\nby Nathan Berkovits (ICTP-SAIFR) a
s part of SFT@Cloud Journal Club\n\n\nAbstract\nI will first review the ve
rsion of open superstring field theory based on the hybrid formalism which
has manifest N=1 d=4 spacetime supersymmetry. I will then discuss two rec
ent applications including the equations of motion for higher-spin massive
fields in an electromagnetic background and the computation of stringy co
rrections to the self-dual d=4 instanton solution.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ashoke Sen (ICTS-TIFR\, Bengaluru)
DTSTART:20220127T140000Z
DTEND:20220127T153000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/4
DESCRIPTION:Title: D-instanton amplitudes\nby Ashoke Sen (ICTS-TIFR\, Beng
aluru) as part of SFT@Cloud Journal Club\n\n\nAbstract\nI'll describe the
general procedure for computing D-instanton amplitudes in string theory\,
with a special focus on type II string theories compactified on Calabi-Yau
manifolds.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yuji Okawa (Institute of Physics\, University of Tokyo)
DTSTART:20220210T140000Z
DTEND:20220210T153000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/5
DESCRIPTION:Title: Renormalization of one-loop scattering amplitudes in scarla
r field theories via homotopy algebras\nby Yuji Okawa (Institute of Ph
ysics\, University of Tokyo) as part of SFT@Cloud Journal Club\n\n\nAbstra
ct\nWhen actions are written in terms of homotopy algebras such as $A_\\in
fty$ algebras and $L_\\infty$ algebras\, expressions of on-shell scatterin
g amplitudes in perturbation theory are universal for both string field th
eories and ordinary field theories. In this talk\, we describe the renorma
lization of one-loop scattering amplitudes in $\\phi^3$ theory using an $A
_\\infty$ algebra.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ivo Sachs (LMU\, Munich)
DTSTART:20220224T140000Z
DTEND:20220224T153000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/6
DESCRIPTION:by Ivo Sachs (LMU\, Munich) as part of SFT@Cloud Journal Club\
n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Raghu Mahajan (Stanford University)
DTSTART:20220407T130000Z
DTEND:20220407T143000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/7
DESCRIPTION:Title: Semiclassical evaluation of the vacuum sphere and the FZZT
disk path integrals in noncritical string theory\nby Raghu Mahajan (St
anford University) as part of SFT@Cloud Journal Club\n\n\nAbstract\nWe com
pute the vacuum sphere and the FZZT disk partition functions in noncritica
l string theory in the semiclassical limit. The worldsheet theory consists
of the $(2\,p)$ minimal model\, the Liouville field and the usual bc ghos
ts. The semiclassical limit is the limit of large p\, in which the central
charge of the Liouville sector goes to plus infinity\, and the path integ
ral can be done via the saddle point method. The main conceptual point is
that the unfixed $PSL(2\,C)$ and $PSL(2\,R)$ gauge groups are spontaneousl
y broken by the saddle point configuration of the Liouville field\, which
removes the usual obstacles in computing these path integrals in critical
string theory. The quantity $sphere/disk^2$ is free of all normalization a
mbiguities and we find a precise numerical match between the string theory
answer and the answer from the dual double-scaled one-matrix integral. (T
his talk is based on work with Douglas Stanford and Cynthia Yan.)\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Oliver Schlotterer (Uppsala university)
DTSTART:20220519T130000Z
DTEND:20220519T143000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/8
DESCRIPTION:Title: Recent developments in superstring loop amplitudes\nby
Oliver Schlotterer (Uppsala university) as part of SFT@Cloud Journal Club\
n\n\nAbstract\nIn this talk\, I will review motivations\, results\, and st
rategies for loop amplitudes in superstring theories. Based on chiral spli
tting of correlation functions of closed-string vertex operators\, a simpl
ified result will be presented for two-loop five-point amplitudes involvin
g massless type-II states.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Edward Witten (IAS Princeton)
DTSTART:20220310T140000Z
DTEND:20220310T153000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/9
DESCRIPTION:Title: No Ensemble Averaging Below the Black Hole Threshold\nb
y Edward Witten (IAS Princeton) as part of SFT@Cloud Journal Club\n\n\nAbs
tract\nIn the AdS/CFT correspondence\, amplitudes associated to connected
bulk manifolds with disconnected boundaries have presented a longstanding
mystery. A possible interpretation is that they reflect the effects of ave
raging over an ensemble of boundary theories. But in examples in dimension
D≥3\, an appropriate ensemble of boundary theories does not exist. Here
we sharpen the puzzle by identifying a class of "sub-threshold" observabl
es that we claim do not show effects of ensemble averaging. These are ampl
itudes that do not involve black hole states. To support our claim\, we ex
plore the example of D=3\, and show that connected solutions of Einstein's
equations with disconnected boundary never contribute to sub-threshold ob
servables. To demonstrate this requires some novel results about the renor
malized volume of a hyperbolic three-manifold\, which we prove using moder
n methods in hyperbolic geometry. Why then do any observables show apparen
t ensemble averaging? We propose that this reflects the chaotic nature of
black hole physics and the fact that the Hilbert space describing a black
hole does not have a large N limit.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nima Arkani-Hamed (IAS\, Princeton)
DTSTART:20220421T130000Z
DTEND:20220421T143000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/10
DESCRIPTION:Title: On Unitarity of Tree-Level String Amplitudes\nby Nima
Arkani-Hamed (IAS\, Princeton) as part of SFT@Cloud Journal Club\n\n\nAbst
ract\nFour-particle tree-level scattering amplitudes in string theory are
magically consistent with unitarity\, reflected in the non-trivial fact th
at beneath the critical dimension\, the residues of the amplitudes on mass
ive poles can be expanded in partial waves with all positive coefficients.
While this follows (rather indirectly) from the no-ghost theorem\, the si
mplicity of the statement and its fundamental importance for the physical
consistency of string theory begs for a more direct and elementary underst
anding. In this note we take a step in this direction by presenting a new
expression for the partial wave coefficients of string amplitudes\, given
by surprisingly simple double/triple contour integrals for open/closed str
ings. This representation allows us to directly prove unitarity of all sup
erstring theories in $D \\leq 6$ spacetime dimensions\, and can also be us
ed to determine various asymptotics of the partial waves at large mass lev
els.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hiroshi Kunitomo (Kyoto University)
DTSTART:20220602T120000Z
DTEND:20220602T133000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/11
DESCRIPTION:Title: Open-closed Homotopy Algebra in Superstring Field Theory\nby Hiroshi Kunitomo (Kyoto University) as part of SFT@Cloud Journal Cl
ub\n\n\nAbstract\nWe construct open-closed superstring interactions based
on the open-closed homotopy algebra structure. It provides a classical ope
n superstring field theory on general closed-superstring field backgrounds
described by classical solutions of the nonlinear equations of motion of
the closed superstring field theory.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Atakan Hilmi Fırat (MIT)
DTSTART:20220505T130000Z
DTEND:20220505T143000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/12
DESCRIPTION:Title: D-instanton Induced Superpotential\nby Atakan Hilmi F
ırat (MIT) as part of SFT@Cloud Journal Club\n\n\nAbstract\nIn this talk\
, I will explain how one can fix the normalization of the D-instanton cont
ribution to the superpotential in type II string theory on Calabi-Yau orie
ntifolds using string field theory and show such normalization is holomorp
hic function of the moduli. Along the way I will sketch the proof for a f
olk theorem relating D-instantons to space-filling D-branes on Calabi-Yau'
s. Lastly\, I will argue for the absence of multi-instanton contribution t
o the superpotential in these scenarios. Based on 2204.02981.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kevin Costello (Perimeter Institute)
DTSTART:20230525T130000Z
DTEND:20230525T143000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/13
DESCRIPTION:Title: Twisted supergravity and string field theory\nby Kevin
Costello (Perimeter Institute) as part of SFT@Cloud Journal Club\n\n\nAbs
tract\nTwisted supergravity is ordinary supergravity in a background where
the superghost has a vev. I will review what is known about twisted super
gravity. I will also discuss some joint work with Si Li\, where we give a
string field theory inspired argument for how to quantize twisted IIB sup
ergravity.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Aron Wall (DAMTP\, Cambridge University)
DTSTART:20230126T140000Z
DTEND:20230126T153000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/15
DESCRIPTION:Title: The Off-Shell String Effective Action\nby Aron Wall (D
AMTP\, Cambridge University) as part of SFT@Cloud Journal Club\n\n\nAbstra
ct\nTaking string theory off shell requires breaking Weyl invariance on th
e worldsheet\, i.e. the worldsheet theory is now a QFT instead of a CFT.
I will explain Tseytlin's approach to taking the worldsheet theory off-she
ll in a consistent manner\, with a particular emphasis on the subtleties i
nvolved in calculating the sphere amplitude. This approach allows for the
derivation of a classical string action which gives rise to the correct e
quations of motion and S-matrix\, to all orders in perturbation theory. I
will also attempt to explain how the resulting off-shell effective tree a
mplitudes are related to string field theory. Based on arXiv:2211.08607.\
n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Amr Ahmadain (DAMTP\, Cambridge University)
DTSTART:20230209T140000Z
DTEND:20230209T153000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/16
DESCRIPTION:Title: Off-shell Strings and Black Hole Entropy\nby Amr Ahmad
ain (DAMTP\, Cambridge University) as part of SFT@Cloud Journal Club\n\n\n
Abstract\nIn this talk\, after reviewing Tseytlin's prescriptions for cons
tructing classical (sphere) off-shell effective actions\, I'll explain the
underlying conceptual structure of the Susskind and Uglum black hole entr
opy argument. There I will show explicitly how the classical (tree-level)
effective action and entropy $S = A/4G_N$ may be calculated from the spher
e diagrams. We also discuss the behaviour of the Susskind and Uglum entro
py under RG flow. Although the conical manifold smooths out under RG flow
\, moving towards an on-shell configuration\, the entropy doesn't change.
\n\nI will also compare these off-shell results with the much more popular
orbifold method for calculating entropy from the on-shell $C/Z_N$ backgro
und. By considering processes involving twisted string states (basically\,
the orbifold conserves twist and hence does not allow twisted strings to
pinch off at the tip\, while the off-shell NLSM of a slightly smoothed-out
cone obviously does allow this process)\, I will conclude that the orbifo
ld backgrounds are fundamentally different from conical backgrounds at the
same value of inverse temperature $\\beta$---unless one allows tachyons t
o condense on the orbifold.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hong Liu (MIT)
DTSTART:20230223T140000Z
DTEND:20230223T153000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/17
DESCRIPTION:Title: Subalgebra-subregion duality: emergence of space and time
in holography\nby Hong Liu (MIT) as part of SFT@Cloud Journal Club\n\n
\nAbstract\nIn holographic duality\, a higher dimensional quantum gravity
system emerges from a lower dimensional conformal field theory (CFT) with
a large number of degrees of freedom. We propose a formulation of duality
for a general causally complete bulk spacetime region\, called subalgebra
-subregion duality\, which provides a framework to describe how geometric
notions in the gravity system\, such as spacetime subregions\, different n
otions of times\, and causal structure\, emerge from the dual CFT. Subalge
bra-subregion duality generalizes and brings new insights into subregion-s
ubregion duality (or\, equivalently\, entanglement wedge reconstruction).
It provides a mathematically precise definition of subregion-subregion dua
lity and gives an independent definition of entanglement wedges without us
ing entropy. Geometric properties of entanglement wedges\, including those
that play a crucial role in interpreting the bulk as a quantum error corr
ecting code\, can be understood from the duality as the geometrization of
the additivity anomaly of certain algebras.\nUsing general boundary subalg
ebras rather than those associated with geometric subregions makes it poss
ible to find duals for general bulk spacetime regions\, including those no
t touching the boundary. Applying subalgebra-subregion duality to a bounda
ry state describing a single-sided black hole also provides a precise way
to define mirror operators.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nobuyuki Ishibashi (Tsukuba University)
DTSTART:20230309T120000Z
DTEND:20230309T133000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/18
DESCRIPTION:Title: The Fokker-Planck formalism for closed bosonic strings
\nby Nobuyuki Ishibashi (Tsukuba University) as part of SFT@Cloud Journal
Club\n\n\nAbstract\nEvery Riemann surface with genus $g$ and $n$ punctures
admits a hyperbolic metric if $2g-2+n>0$. Such a surface can be decompose
d into pairs of pants whose boundaries are geodesics. We construct a strin
g field theory for closed bosonic strings based on this pants decompositio
n.\n\nIn order to do so\, we derive a recursion relation satisfied by the
off-shell amplitudes\, using Mirzakhani's scheme for computing integrals o
ver the moduli space of bordered Riemann surfaces. The recursion relation
can be turned into a string field theory via the Fokker-Planck formalism.
The Fokker-Planck Hamiltonian consists of kinetic terms and three string v
ertices.\n\nUnfortunately\, the worldsheet BRST symmetry is not manifest i
n the theory thus constructed. We will show that the invariance can be mad
e manifest by introducing auxiliary fields.\n\nNote unusual time.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Piotr Tourkine (Université de Savoie)
DTSTART:20230323T140000Z
DTEND:20230323T153000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/19
DESCRIPTION:Title: Integrands\, monodromies\, and loop momentum in string amp
litude\nby Piotr Tourkine (Université de Savoie) as part of SFT@Cloud
Journal Club\n\n\nAbstract\nMonodromy relations relate different ordering
s of open string amplitudes at tree-level. These relations originate from
the mutlivaluedness of the open-string integrand and are fundamental to un
derstanding the famous KLT relations\, which allow the explanation of clos
ed-string amplitudes factorising into a product of open-string amplitudes.
Upon the field theory limit\, this relates to the double-copy formalism\,
which has been instrumental in the progress in the calculations of gravit
ational scattering amplitudes over the last 15 years.\n\nAt loop-level\, w
e showed how the monodromy relations are naturally expressed in terms of l
oop-momentum\, and they relate graphs with different orderings and topolog
ies. This raises some immediate problems: from the Feynman diagram intuiti
on\, loop momenta in different graphs are not supposed to have anything to
do with each other\, and therefore the monodromy relations might be ambig
uous.\n\nIn this talk\, I will explain that this is not the case and that
the formalism used to introduce loop momentum\, chiral splitting\, defines
a global loop momentum. One consequence is that\, upon the field theory l
imit\, a similar global choice exists in field theory as well. I will star
t by reviewing the monodromy relations and chiral splitting\, and then I
’ll elaborate on this definition of the loop momentum and relations to t
he field theory limit and double-copy procedure.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Manki Kim (MIT)
DTSTART:20230504T130000Z
DTEND:20230504T143000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/20
DESCRIPTION:Title: Some difficult problems in string compactifications and st
ring phenomenology\nby Manki Kim (MIT) as part of SFT@Cloud Journal Cl
ub\n\n\nAbstract\nIn this talk\, I will describe a few important open prob
lems in string phenomenology. I will describe how some of the problems may
benefit from recent developments in string field theory.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cumrun Vafa (Harvard University)
DTSTART:20230406T130000Z
DTEND:20230406T143000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/21
DESCRIPTION:Title: String Theory and Our Universe\nby Cumrun Vafa (Harvar
d University) as part of SFT@Cloud Journal Club\n\n\nAbstract\nString theo
ry landscape of vacua point to new consistency conditions that a quantum g
ravitational system must satisfy. There are only a small number of quantu
m field theories that satisfy these conditions\, and all the rest belong t
o the `Swampland'\, which cannot be consistently coupled to gravity. In t
his talk\, I review some of these conditions and their implications for co
smology and particle physics.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Keith R. Dienes (The University of Arizona)
DTSTART:20230420T130000Z
DTEND:20230420T143000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/22
DESCRIPTION:Title: UV/IR Mixing\, EFTs\, Hidden Cancellations\, and Origami:
Calculating the Higgs Mass and Gauge-Coupling Running in String Theory\nby Keith R. Dienes (The University of Arizona) as part of SFT@Cloud Jou
rnal Club\n\n\nAbstract\nIn this talk\, we shall present a non-technical m
ethod of understanding UV/IR mixing from a field-theoretic perspective. W
e will then discuss how these ideas are ultimately realized in string theo
ry\, providing a self-contained introduction to relevant string ideas as w
e proceed. Finally\, we shall present a fully string-theoretic framewor
k for calculating one-loop Higgs masses directly from the first principles
in perturbative closed string theories. Notably\, using our framework\,
we find that a gravitational modular anomaly generically relates the Higgs
mass to the one-loop cosmological constant\, thereby yielding a string-th
eoretic connection between the two fundamental quantities\, which are know
n to suffer from hierarchy problems in the absence of spacetime supersymme
try. \n\nWe also discuss a number of crucial issues involving the use and
interpretation of regulators in UV/IR-mixed theories\, such as string theo
ry\, and the manner in which one can extract an EFT description from such
theories. Finally\, we analyze the running of the Higgs mass within such a
n EFT description and uncover the existence of a "dual IR" region which em
erges at high energies as the consequence of an intriguing scale-inversion
duality symmetry. We also identify a generic stringy effective potential
for the Higgs fields in such theories. Our results can therefore serve a
s the launching point for a rigorous investigation of gauge hierarchy prob
lems in string theory.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Olaf Hohm (Humboldt University)
DTSTART:20231026T130000Z
DTEND:20231026T143000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/23
DESCRIPTION:Title: Double Copy\, Double Field Theory & Homotopy Algebras\
nby Olaf Hohm (Humboldt University) as part of SFT@Cloud Journal Club\n\n\
nAbstract\nThe double copy denotes a technology to relate the scattering a
mplitudes of Yang-Mills theory to those of gravity. While enormously succe
ssful at the level of scattering amplitudes\, until recently there was no
first-principle understanding of how to derive such relations. Such an und
erstanding would be needed in order to describe\, for instance\, a double
copy of classical solutions. I present an approach based on homotopy algeb
ras such as L-infinity algebras that allows one to provide such a first-pr
inciple derivation\, at least to some finite order in perturbation theory.
To this end I review how to formulate Yang-Mills theory as an L-infinity
algebra\, how to "strip off" color to obtain a different kind of homotopy
algebra and\, finally\, how to combine two copies of these exotic algebras
to obtain the L-infinity algebra of gravity in the form of double field t
heory.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Minjae Cho (Princeton University)
DTSTART:20231116T140000Z
DTEND:20231116T153000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/24
DESCRIPTION:Title: On the symplectic form of the open string field theory
\nby Minjae Cho (Princeton University) as part of SFT@Cloud Journal Club\n
\n\nAbstract\nWe explore the construction of the symplectic form on the ph
ase space of classical solutions in open string field theory. We demonstra
te its practical application by computing the energy of open string rollin
g tachyon solutions\, which agrees with Sen’s proposal based on boundary
conformal field theory.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Georg Stettinger (Institute of Physics of The Czech Academy of Sci
ences)
DTSTART:20240125T140000Z
DTEND:20240125T153000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/25
DESCRIPTION:Title: Open String Field Theory with Stubs\nby Georg Stetting
er (Institute of Physics of The Czech Academy of Sciences) as part of SFT@
Cloud Journal Club\n\n\nAbstract\nThere are various reasons why adding stu
bs to the vertices of open string field theory (OSFT) is \ninteresting: No
t only can the stubs tame certain singularities and make the theory more w
ell-behaved\, but also the new theory shares a lot of similarities with cl
osed string field\ntheory\, which helps to improve our understanding of it
s structure and possible solutions. In this talk\, I will explain in detai
l how to implement stubs into the framework of OSFT\, resulting in an\nA-i
nfinity-algebra with infinitely many vertices. Moreover\, properties and e
xamples of cohomomorphisms that map solutions of Witten theory to solution
s of the stubbed theory are discussed. In the second part\, I will general
ize the whole construction to the sliver frame and construct solutions of
the stubbed theory explicitly.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Aninda Sinha (Indian Institute of Science)
DTSTART:20240222T140000Z
DTEND:20240222T153000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/26
DESCRIPTION:Title: From Euler to Veneziano and Back\nby Aninda Sinha (Ind
ian Institute of Science) as part of SFT@Cloud Journal Club\n\n\nAbstract\
nWhat links Madhava\, Euler\, and string theory? I will present new QFT mo
tivated representations of the Euler Beta function and related functions w
hich make appearances in string theory. Pushing the analogy between Feynma
n diagrams in quantum field theory and string theory leads to new physics
inspired representations of Zeta functions as well as pi\, finding that th
e QFT formulas interpolate between standard representations and faster con
verging ones. The new representations sum over all channels and include co
ntact interactions very much in the spirit of quantum field theory and wha
t is anticipated from string field theory\, enabling efficient level trunc
ation. I will briefly touch upon the status of this calculation in string
field theory and what is missing to enable a derivation of an analytic for
mula using string field theory.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lucien Heurtier (King's College London)
DTSTART:20240418T130000Z
DTEND:20240418T143000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/27
DESCRIPTION:Title: Exact Schwinger Proper Time Renormalisation\nby Lucien
Heurtier (King's College London) as part of SFT@Cloud Journal Club\n\n\nA
bstract\nWe derive an exact version of the Schwinger Proper Time Renormali
sation Group flow equation from first principles from the complete path in
tegral\, without using any perturbative expansion. We study the advantages
of this flow equation as compared to the canonical Exact Renormalisation
Group flow equation\, which uses a regulator in momentum space. We use our
flow equation to recover the convexity of the effective scalar potential
in the IR limit and apply it to the study of false-vacuum decay.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alberto Ruffino (Università di Torino)
DTSTART:20240328T140000Z
DTEND:20240328T153000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/28
DESCRIPTION:Title: Quantum Stubs for String Field Theories\nby Alberto Ru
ffino (Università di Torino) as part of SFT@Cloud Journal Club\n\n\nAbstr
act\nWe present a systematic algebraic procedure for adding stubs to a gen
eric quantum String Field Theory. This method extends the approach of addi
ng stubs through homotopy transfer techniques\, as pointed out by Schnabl-
Stettinger and Erbin-Firat\, to the quantum scenario. To start with\, we p
edagogically apply our method to a “quantum” cubic theory and then del
ve into proper solutions to the BV quantum master equation\, such as open-
closed SFT\, where we extract the explicit expression for the stubbed mult
i-string open-closed products. We also describe how our algebraic method m
atches the geometric interpretation of adding stubs\, focusing on the conc
rete example of the open string one-loop tadpole within the framework of o
pen-closed SFT.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michael Kroyter (Holon Institute of Technology)
DTSTART:20240425T130000Z
DTEND:20240425T143000Z
DTSTAMP:20260404T110830Z
UID:SFT_at_cloud_JC/29
DESCRIPTION:Title: On Democratic String Field Theories\nby Michael Kroyte
r (Holon Institute of Technology) as part of SFT@Cloud Journal Club\n\n\nA
bstract\nWe reexamine democratic open string field theories\, namely\, the
ories in which string fields are not constrained to a single picture numbe
r and picture changing is obtained as a gauge transformation. We describe
several possibilities for regular free theories and attempt to construct t
he lowest order interaction term and identify the lowest order gauge trans
formation for some of these theories. We also discuss projections over str
ing field spaces that might be needed for a consistent off-shell implement
ation of picture changing.\n
LOCATION:https://stable.researchseminars.org/talk/SFT_at_cloud_JC/29/
END:VEVENT
END:VCALENDAR