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SUMMARY:George Zahariade (Arizona State University)
DTSTART:20200612T180000Z
DTEND:20200612T190000Z
DTSTAMP:20260404T111136Z
UID:HEP_TH_PH_COSMO_NUCL/1
DESCRIPTION:Title: Quantum Mechanics of Gravitational Waves\nby Georg
e Zahariade (Arizona State University) as part of ASU Cosmology & Beyond S
eminars\n\n\nAbstract\nIn recent work with Maulik Parikh and Frank Wilczek
we study the effect of a quantized gravitational wave on a LIGO-type grav
itational wave detector. We find that the arm-length is subject to a stoch
astic tidal force whose properties depend on the exact quantum state of th
e gravitational wave\, if gravitational waves are quantized. The quantum n
ature of gravitational waves may be detectable as an additional noise sour
ce in gravitational wave detectors.\n
LOCATION:https://stable.researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Geoffrey Penington (UC\, Berkeley)
DTSTART:20200909T210000Z
DTEND:20200909T220000Z
DTSTAMP:20260404T111136Z
UID:HEP_TH_PH_COSMO_NUCL/2
DESCRIPTION:Title: Replica wormholes\, entanglement wedges and the black
hole information paradox\nby Geoffrey Penington (UC\, Berkeley) as par
t of ASU Cosmology & Beyond Seminars\n\n\nAbstract\nHawking famously argue
d\, based on semiclassical calculations\, that the radiation from evaporat
ing black holes is always perfectly thermal and contains no information ab
out the matter that fell in. Such a result is inconsistent with the unitar
ity of quantum mechanics. In this talk\, I will argue that a more careful
replica trick calculation shows that the gravitational path integral becom
es dominated at late times by saddles containing spacetime wormholes. Thes
e wormholes cause the entropy to decrease after the Page time\, consistent
with unitarity\, and allow information to escape from the interior of the
black hole. In very simple toy models\, we can evaluate the path integral
exactly\, and see the information emerge. In more realistic black holes\,
the full wormhole solutions cannot be found explicitly. However\, their e
xistence\, and their most important consequences\, can be derived by study
ing the location and properties of a non-trivial ‘quantum extremal surfa
ce’ in the original Hawking solution\n
LOCATION:https://stable.researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tom Kephart (Vanderbilt University)
DTSTART:20200923T210000Z
DTEND:20200923T220000Z
DTSTAMP:20260404T111136Z
UID:HEP_TH_PH_COSMO_NUCL/3
DESCRIPTION:Title: Antichirp: Gravitational Waves from a Black Hole Orbit
ing in a Wormhole Geometry\nby Tom Kephart (Vanderbilt University) as
part of ASU Cosmology & Beyond Seminars\n\n\nAbstract\nAfter a brief revie
w of black hole--black hole mergers\, and some background on wormholes and
their construction\, we discuss the case of a black hole orbiting a wormh
ole and the gravitational waves emitted. Results are based on recent work
in collaboration with James Dent\, Bill Gabella and Kelly Holly-Bockelm
ann (arXiv:2007.09135).\n
LOCATION:https://stable.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:20260404T111136Z
UID:HEP_TH_PH_COSMO_NUCL/4
DESCRIPTION:Title: The NANOGrav search for nanohertz gravitational waves<
/a>\nby Xavier Siemens (Center for Gravitation\, Cosmology\, and Astrophys
ics\, University of Wisconsin) as part of ASU Cosmology & Beyond Seminars
\n\n\nAbstract\nSupermassive black hole binaries (SMBHBs)\, and possibly o
ther sources\,\ngenerate gravitational waves in the nanohertz part of the
spectrum. For over a\ndecade and a half the North American Nanohertz Obser
vatory for Gravitational Waves\n(NANOGrav) has been using the Green Bank T
elescope\, the Arecibo Observatory\,\nand\, more recently\, the Very Large
Array to observe millisecond pulsars. Our\ngoal is to directly detect nan
ohertz gravitational waves\, which cause small\ncorrelated perturbations t
o the times of arrival of radio pulses from millisecond\npulsars. We curre
ntly monitor almost 80 millesecond pulsars with sub-microsecond\nprecision
and weekly to monthly cadences. I will present an overview of NANOGrav
\nPhysics Frontiers Center activities and summarize the results of our mos
t recent\nsearch for a stochastic background of gravitational-waves on the
12.5-yr dataset.\n
LOCATION:https://stable.researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sergey Ketov (Tokyo Metropolitan University and Kavli IPMU\, Japan
)
DTSTART:20201105T000000Z
DTEND:20201105T010000Z
DTSTAMP:20260404T111136Z
UID:HEP_TH_PH_COSMO_NUCL/5
DESCRIPTION:Title: Starobinsky inflation\, primordial black holes and ind
uced gravitational waves from modified supergravity\nby Sergey Ketov (
Tokyo Metropolitan University and Kavli IPMU\, Japan) as part of ASU Cosmo
logy & Beyond Seminars\n\n\nAbstract\nBasic (Starobinsky) inflationary mod
el is reviewed as the theoretical probe of a more fundamental theory of gr
avity. Modified supergravity is introduced as an example of such theory to
wards a deeper understanding of cosmological inflation and (possible) form
ation of primordial black holes in the early Universe. A specific model of
both phenomena in modified supergravity is proposed and investigated in d
etail. 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 semina
r is designed for those who are interested in theoretical cosmology and as
trophysics\, theoretical high energy physics\, gravitational theory and st
ring theory.\n
LOCATION:https://stable.researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ofri Telem (Berkeley Center for Theoretical Physics\, University o
f California\, Berkeley)
DTSTART:20201111T210000Z
DTEND:20201111T220000Z
DTSTAMP:20260404T111136Z
UID:HEP_TH_PH_COSMO_NUCL/6
DESCRIPTION:Title: Axion Strings are Superconducting\nby Ofri Telem (
Berkeley Center for Theoretical Physics\, University of California\, Berke
ley) as part of ASU Cosmology & Beyond Seminars\n\n\nAbstract\nWe explore
the cosmological consequences of the superconductivity of QCD axion string
s. Axion strings can support a sizeable chiral electric current and charge
\, which alters their early universe dynamics. Shrinking axion string loop
s can become effectively stable remnants called vortons\, supported by the
electromagnetic force of the string current. Generically\, vortons produ
ced by axion strings overclose the universe\, unless there are efficient c
urrent leakage processes. Furthermore\, if a primordial magnetic field (PM
F) exists in the early universe\, a large current is induced on axion stri
ngs\, creating a significant drag force from interactions with the surroun
ding plasma. As a result\, the strings are slowed down\, which leads to an
orders of magnitude enhancement in the number of strings per Hubble volum
e. Finally\, we study the implications for the QCD axion relic abundance.
The QCD axion window is shifted by orders of magnitude in some parts of ou
r parameter space.\n
LOCATION:https://stable.researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anupam Mazumdar (Van Swinderen Institute\, University of Groningen
)
DTSTART:20201216T210000Z
DTEND:20201216T220000Z
DTSTAMP:20260404T111136Z
UID:HEP_TH_PH_COSMO_NUCL/7
DESCRIPTION:Title: Witnessing Quantum gravity in a laboratory via miniatu
rist quantum accelerator\nby Anupam Mazumdar (Van Swinderen Institute\
, University of Groningen) as part of ASU Cosmology & Beyond Seminars\n\n\
nAbstract\nUnveiling the nature of spacetime remains one of the final fron
tiers of modern theoretical physics. I will discuss how to witness the qua
ntum nature of gravity in a table-top experiment by creating the right wit
ness involving the two neutral masses (spin embedded) undergoing through t
he Stern-Gerlach apparatus. I will discuss various challenges involved in
pursuing the dream of witnessing graviton and the critical challenges. The
re are many challenges to be met and I will discuss the important ones: (1
) To create a macroscopic quantum superposition of heavy masses via the S
tern-Gerlach setup while controlling the stray gravitational acceleration
and the gravity gradient noise\, (2) Precise constraints on the magnetic f
ield/current such that various electromagnetic interactions are under cont
rol\, (3) Vacuum dominated Casimir effect which will create the main backg
round for the experiment\, (4) Constraints on vacuum and temperatures\, (5
) Feasibility of the experiment in a drop-tower\, (6) The material propert
ies and patch potentials. I will briefly discuss time scales for realising
such an accelerator which will witness for the first time the graviton in
a terrestrial laboratory.\n\nThere is not password to enter the zoom link
. Some etiquete rules: Please show your full name on the zoom window\, unl
ess you are asking a question or making a comment keep your mic mute\, ope
n up your camera and show your face when asking a question.\n
LOCATION:https://stable.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:20260404T111136Z
UID:HEP_TH_PH_COSMO_NUCL/8
DESCRIPTION:Title: Constraints on the primordial hypermagnetic fields fro
m the baryon isocurvature perturbations\nby Kohei Kamada (Research Cen
ter for the Early Universe\, The University of Tokyo\, Tokyo.) as part of
ASU Cosmology & Beyond Seminars\n\n\nAbstract\nGamma-ray observations of b
lazars suggest the existence of the intergalactic magnetic fields and thei
r origin is interest for both astro physicsts and cosmologists. Among seve
ral proposals\, magnetogenesis in the early Universe is an interesting opt
ion since it might also be a probe for the physics beyond the Standard Mod
el of particle physics. \nRecently\, it has also been proven that the bary
on asymmetry of the Universe can be also generated if the magnetic fields
are produced before the electroweak symmetry breaking with helicity withou
t imposing any new physics. \nHowever\, baryon isocurvature perturbations
are also generated at the scale of the magnetic field coherence length in
the meantime\, which is constrained by the inhomogeneous Big Bang Nucleosy
nthesis. Note that this is an inevitable consequence of the Standard Model
of particle physics. \nIn this talk\, I give generic constraints of the h
ypermagnetic field properties generated before the electroweak symmetry br
eaking. \nNoting that the baryon isocurvature perturbations are generated
even from non-helical magnetic fields\, I show that with reasonable parame
ter sets for the Standard Model of particle physics and magnetic field evo
lution laws\, the intergalactic magnetic fields suggested by the blazar ob
servations are hardly explained solely by the hypermagnetic fields generat
ed before the electroweak symmetry breaking. \nHelical hypermagnetic field
s can still be the origin of the present baryon asymmetry of the Universe\
, but we need an additional magnetogenesis or an unknown magnetic field am
plification mechanism.\n\nThere is not need to register\, but the followin
g passcode should be used. 830859\n
LOCATION:https://stable.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:20260404T111136Z
UID:HEP_TH_PH_COSMO_NUCL/9
DESCRIPTION:Title: Axion Cosmic Strings: Players in the Early Universe?<
/a>\nby Michael Dine (Santa Cruz Institute for Particle Physics and Depart
ment of Physics\, University of California at Santa Cruz) as part of ASU C
osmology & Beyond Seminars\n\n\nAbstract\nAxion cosmic strings have long b
een considered as a potential source of enhancement of axion dark matter p
roduction\, and have been\nthe subject of extensive simulations in recent
years. But axion strings are rather peculiar entities. We explore some a
spects of these\nobjects\, and suggest that they may not play a distinguis
hed role in early universe cosmology.\n\nThere is not need to register\, b
ut the following passcode should be used: 830859.\nPlease follow the usual
etiquette rules: Show your full name in Zoom window\, mute your mic upon
entrance to the Zoom room\, open your camera when asking questions.\n
LOCATION:https://stable.researchseminars.org/talk/HEP_TH_PH_COSMO_NUCL/9/
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