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SUMMARY:George Zahariade (Arizona State University)
DTSTART:20200612T180000Z
DTEND:20200612T190000Z
DTSTAMP:20260422T230722Z
UID:HEP_TH_PH_COSMO_NUCL/1
DESCRIPTION:Title: Quantum Mechanics of Gravitational Waves\nby George Zahar
iade (Arizona State University) as part of ASU Cosmology & Beyond Seminars
\n\n\nAbstract\nIn recent work with Maulik Parikh and Frank Wilczek we stu
dy the effect of a quantized gravitational wave on a LIGO-type gravitation
al wave detector. We find that the arm-length is subject to a stochastic t
idal force whose properties depend on the exact quantum state of the gravi
tational wave\, if gravitational waves are quantized. The quantum nature o
f gravitational waves may be detectable as an additional noise source in g
ravitational wave detectors.\n
LOCATION:https://researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Geoffrey Penington (UC\, Berkeley)
DTSTART:20200909T210000Z
DTEND:20200909T220000Z
DTSTAMP:20260422T230722Z
UID:HEP_TH_PH_COSMO_NUCL/2
DESCRIPTION:Title: Replica wormholes\, entanglement wedges and the black hole in
formation paradox\nby Geoffrey Penington (UC\, Berkeley) as part of AS
U Cosmology & Beyond Seminars\n\n\nAbstract\nHawking famously argued\, bas
ed on semiclassical calculations\, that the radiation from evaporating bla
ck holes is always perfectly thermal and contains no information about the
matter that fell in. Such a result is inconsistent with the unitarity of
quantum mechanics. In this talk\, I will argue that a more careful replica
trick calculation shows that the gravitational path integral becomes domi
nated at late times by saddles containing spacetime wormholes. These wormh
oles cause the entropy to decrease after the Page time\, consistent with u
nitarity\, and allow information to escape from the interior of the black
hole. In very simple toy models\, we can evaluate the path integral exactl
y\, and see the information emerge. In more realistic black holes\, the fu
ll wormhole solutions cannot be found explicitly. However\, their existenc
e\, and their most important consequences\, can be derived by studying the
location and properties of a non-trivial ‘quantum extremal surface’ i
n the original Hawking solution\n
LOCATION:https://researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tom Kephart (Vanderbilt University)
DTSTART:20200923T210000Z
DTEND:20200923T220000Z
DTSTAMP:20260422T230722Z
UID:HEP_TH_PH_COSMO_NUCL/3
DESCRIPTION:Title: Antichirp: Gravitational Waves from a Black Hole Orbiting in
a Wormhole Geometry\nby Tom Kephart (Vanderbilt University) as part of
ASU Cosmology & Beyond Seminars\n\n\nAbstract\nAfter a brief review of bl
ack hole--black hole mergers\, and some background on wormholes and their
construction\, we discuss the case of a black hole orbiting a wormhole and
the gravitational waves emitted. Results are based on recent work in col
laboration with James Dent\, Bill Gabella and Kelly Holly-Bockelmann (ar
Xiv:2007.09135).\n
LOCATION:https://researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Xavier Siemens (Center for Gravitation\, Cosmology\, and Astrophys
ics\, University of Wisconsin)
DTSTART:20201014T210000Z
DTEND:20201014T220000Z
DTSTAMP:20260422T230722Z
UID:HEP_TH_PH_COSMO_NUCL/4
DESCRIPTION:Title: The NANOGrav search for nanohertz gravitational waves\nby
Xavier Siemens (Center for Gravitation\, Cosmology\, and Astrophysics\,
University of Wisconsin) as part of ASU Cosmology & Beyond Seminars\n\n\nA
bstract\nSupermassive black hole binaries (SMBHBs)\, and possibly other so
urces\,\ngenerate gravitational waves in the nanohertz part of the spectru
m. For over a\ndecade and a half the North American Nanohertz Observatory
for Gravitational Waves\n(NANOGrav) has been using the Green Bank Telescop
e\, the Arecibo Observatory\,\nand\, more recently\, the Very Large Array
to observe millisecond pulsars. Our\ngoal is to directly detect nanohertz
gravitational waves\, which cause small\ncorrelated perturbations to the t
imes of arrival of radio pulses from millisecond\npulsars. We currently mo
nitor almost 80 millesecond pulsars with sub-microsecond\nprecision and we
ekly to monthly cadences. I will present an overview of NANOGrav \nPhysi
cs Frontiers Center activities and summarize the results of our most recen
t\nsearch for a stochastic background of gravitational-waves on the 12.5-y
r dataset.\n
LOCATION:https://researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/4/
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BEGIN:VEVENT
SUMMARY:Sergey Ketov (Tokyo Metropolitan University and Kavli IPMU\, Japan
)
DTSTART:20201105T000000Z
DTEND:20201105T010000Z
DTSTAMP:20260422T230722Z
UID:HEP_TH_PH_COSMO_NUCL/5
DESCRIPTION:Title: Starobinsky inflation\, primordial black holes and induced gr
avitational waves from modified supergravity\nby Sergey Ketov (Tokyo M
etropolitan University and Kavli IPMU\, Japan) as part of ASU Cosmology &
Beyond Seminars\n\n\nAbstract\nBasic (Starobinsky) inflationary model is r
eviewed as the theoretical probe of a more fundamental theory of gravity.
Modified supergravity is introduced as an example of such theory towards a
deeper understanding of cosmological inflation and (possible) formation o
f primordial black holes in the early Universe. A specific model of both p
henomena in modified supergravity is proposed and investigated in detail.
Their observational predictions (including black hole masses\, dark matter
and\ninduced gravitational waves) are derived and compared to the current
and future astrophysical and cosmological observations. The seminar is de
signed for those who are interested in theoretical cosmology and astrophys
ics\, theoretical high energy physics\, gravitational theory and string th
eory.\n
LOCATION:https://researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/5/
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SUMMARY:Ofri Telem (Berkeley Center for Theoretical Physics\, University o
f California\, Berkeley)
DTSTART:20201111T210000Z
DTEND:20201111T220000Z
DTSTAMP:20260422T230722Z
UID:HEP_TH_PH_COSMO_NUCL/6
DESCRIPTION:Title: Axion Strings are Superconducting\nby Ofri Telem (Berkele
y Center for Theoretical Physics\, University of California\, Berkeley) as
part of ASU Cosmology & Beyond Seminars\n\n\nAbstract\nWe explore the cos
mological consequences of the superconductivity of QCD axion strings. Axio
n strings can support a sizeable chiral electric current and charge\, whic
h alters their early universe dynamics. Shrinking axion string loops can b
ecome effectively stable remnants called vortons\, supported by the electr
omagnetic force of the string current. Generically\, vortons produced by
axion strings overclose the universe\, unless there are efficient current
leakage processes. Furthermore\, if a primordial magnetic field (PMF) exis
ts in the early universe\, a large current is induced on axion strings\, c
reating a significant drag force from interactions with the surrounding pl
asma. As a result\, the strings are slowed down\, which leads to an orders
of magnitude enhancement in the number of strings per Hubble volume. Fina
lly\, we study the implications for the QCD axion relic abundance. The QCD
axion window is shifted by orders of magnitude in some parts of our param
eter space.\n
LOCATION:https://researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/6/
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BEGIN:VEVENT
SUMMARY:Anupam Mazumdar (Van Swinderen Institute\, University of Groningen
)
DTSTART:20201216T210000Z
DTEND:20201216T220000Z
DTSTAMP:20260422T230722Z
UID:HEP_TH_PH_COSMO_NUCL/7
DESCRIPTION:Title: Witnessing Quantum gravity in a laboratory via miniaturist qu
antum accelerator\nby Anupam Mazumdar (Van Swinderen Institute\, Unive
rsity of Groningen) as part of ASU Cosmology & Beyond Seminars\n\n\nAbstra
ct\nUnveiling the nature of spacetime remains one of the final frontiers o
f modern theoretical physics. I will discuss how to witness the quantum na
ture of gravity in a table-top experiment by creating the right witness in
volving the two neutral masses (spin embedded) undergoing through the Ster
n-Gerlach apparatus. I will discuss various challenges involved in pursuin
g the dream of witnessing graviton and the critical challenges. There are
many challenges to be met and I will discuss the important ones: (1) To c
reate a macroscopic quantum superposition of heavy masses via the Stern-Ge
rlach setup while controlling the stray gravitational acceleration and the
gravity gradient noise\, (2) Precise constraints on the magnetic field/cu
rrent such that various electromagnetic interactions are under control\, (
3) Vacuum dominated Casimir effect which will create the main background f
or the experiment\, (4) Constraints on vacuum and temperatures\, (5) Feasi
bility of the experiment in a drop-tower\, (6) The material properties and
patch potentials. I will briefly discuss time scales for realising such a
n accelerator which will witness for the first time the graviton in a terr
estrial laboratory.\n\nThere is not password to enter the zoom link. Some
etiquete rules: Please show your full name on the zoom window\, unless you
are asking a question or making a comment keep your mic mute\, open up yo
ur camera and show your face when asking a question.\n
LOCATION:https://researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kohei Kamada (Research Center for the Early Universe\, The Univers
ity of Tokyo\, Tokyo.)
DTSTART:20210127T220000Z
DTEND:20210127T230000Z
DTSTAMP:20260422T230722Z
UID:HEP_TH_PH_COSMO_NUCL/8
DESCRIPTION:Title: Constraints on the primordial hypermagnetic fields from the b
aryon isocurvature perturbations\nby Kohei Kamada (Research Center for
the Early Universe\, The University of Tokyo\, Tokyo.) as part of ASU Cos
mology & Beyond Seminars\n\n\nAbstract\nGamma-ray observations of blazars
suggest the existence of the intergalactic magnetic fields and their origi
n is interest for both astro physicsts and cosmologists. Among several pro
posals\, magnetogenesis in the early Universe is an interesting option sin
ce it might also be a probe for the physics beyond the Standard Model of p
article physics. \nRecently\, it has also been proven that the baryon asym
metry of the Universe can be also generated if the magnetic fields are pro
duced before the electroweak symmetry breaking with helicity without impos
ing any new physics. \nHowever\, baryon isocurvature perturbations are als
o generated at the scale of the magnetic field coherence length in the mea
ntime\, which is constrained by the inhomogeneous Big Bang Nucleosynthesis
. Note that this is an inevitable consequence of the Standard Model of par
ticle physics. \nIn this talk\, I give generic constraints of the hypermag
netic field properties generated before the electroweak symmetry breaking.
\nNoting that the baryon isocurvature perturbations are generated even fr
om non-helical magnetic fields\, I show that with reasonable parameter set
s for the Standard Model of particle physics and magnetic field evolution
laws\, the intergalactic magnetic fields suggested by the blazar observati
ons are hardly explained solely by the hypermagnetic fields generated befo
re the electroweak symmetry breaking. \nHelical hypermagnetic fields can s
till be the origin of the present baryon asymmetry of the Universe\, but w
e need an additional magnetogenesis or an unknown magnetic field amplifica
tion mechanism.\n\nThere is not need to register\, but the following passc
ode should be used. 830859\n
LOCATION:https://researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michael Dine (Santa Cruz Institute for Particle Physics and Depart
ment of Physics\, University of California at Santa Cruz)
DTSTART:20210203T210000Z
DTEND:20210203T220000Z
DTSTAMP:20260422T230722Z
UID:HEP_TH_PH_COSMO_NUCL/9
DESCRIPTION:Title: Axion Cosmic Strings: Players in the Early Universe?\nby
Michael Dine (Santa Cruz Institute for Particle Physics and Department of
Physics\, University of California at Santa Cruz) as part of ASU Cosmolog
y & Beyond Seminars\n\n\nAbstract\nAxion cosmic strings have long been con
sidered as a potential source of enhancement of axion dark matter producti
on\, and have been\nthe subject of extensive simulations in recent years.
But axion strings are rather peculiar entities. We explore some aspects
of these\nobjects\, and suggest that they may not play a distinguished rol
e in early universe cosmology.\n\nThere is not need to register\, but the
following passcode should be used: 830859.\nPlease follow the usual etique
tte rules: Show your full name in Zoom window\, mute your mic upon entranc
e to the Zoom room\, open your camera when asking questions.\n
LOCATION:https://researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/9/
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