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CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VEVENT
DTSTAMP:20200711T182813Z
LAST-MODIFIED:20200319T130853Z
DTSTART:20200320T140000Z
DTEND:20200320T150000Z
UID:event2316@bu.edu
URL:http://physics.bu.edu/events/show/2316
SUMMARY:Nonuniversal entanglement level statistics in projection-driven qua
ntum circuits
DESCRIPTION:Featuring Lei Zhang\, Boston University\, Physics Department\n\
nPart of the Departmental Seminars.\n\nWe study the level-spacing statistic
s in the entanglement spectrum of\noutput states of random universal quantu
m circuits where qubits are\nsubject to a finite probability of projection
to the computational\nbasis at each time step. We encounter two phase trans
itions with\nincreasing projection rate: The first is the volume-to-area la
w\ntransition observed in quantum circuits with projective\nmeasurements; T
he second separates the pure Poisson level statistics\nphase at large proje
ctive measurement rates from a regime of residual\nlevel repulsion in the e
ntanglement spectrum within the area-law\nphase\, characterized by non-univ
ersal level spacing statistics that\ninterpolates between the Wigner-Dyson
and Poisson distributions. By\napplying a tensor network contraction algori
thm \nto the circuit spacetime\, we identify this second\nprojective-measur
ement-driven transition as a percolation transition\nof entangled bonds. Th
e same behavior is observed in both circuits of\nrandom two-qubit unitaries
and circuits of universal gate sets\,\nincluding the set implemented by Go
ogle in its Sycamore circuits.\n\nDissertation Committee: A. E. Ruckenstein
\, C. Chamon\, M. El-Batanouny\, R. Brower (ECE)\n\nLink of Zoom Seminar Ev
ent: https://bostonu.zoom.us/j/957452767
LOCATION: Virtual\, \,
STATUS:CONFIRMED
CLASS:PUBLIC
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20200711T182813Z
LAST-MODIFIED:20200320T160949Z
DTSTART:20200325T180000Z
DTEND:20200325T190000Z
UID:event2318@bu.edu
URL:http://physics.bu.edu/events/show/2318
SUMMARY:Solving Strongly Coupled Quantum Field Theory - Part 1
DESCRIPTION:Featuring Yuan Xin\, Boston University\, Physics Department\n\n
Part of the Departmental Seminars.\n\nThis is the part 1 of two subsequent
presentations. I will focus on introducing the method and discussing a simp
le application on 2D real scalar theory.\n\nQuantum Field Theory is the lan
guage that describes a wide spectrum of physics\, from the fundamental matt
ers and interactions down to the phase transition of water. However\, it is
notoriously hard at strong coupling regime. In this talk I will approach t
his question in an old Quantum Mechanical method - keep a finite number of
states and diagonalize the Hamiltonian as a finite-size matrix - with our r
ecent setup\, known as the Lightcone Conformal Truncation. I will present i
ts applications in various two dimensional examples.\n\nCommittee: Fitzpatr
ick\, Katz\, Laumann\, Sushkov\, Polkovnikov\n\nTopic: Departmental Seminar
of Yuan Xin\nTime: Mar 25\, 2020 02:00 PM Eastern Time (US and Canada)\n\n
Join Zoom Meeting\nhttps://bostonu.zoom.us/j/516244667\n\nMeeting ID: 516 2
44 667
LOCATION: \, \,
STATUS:CONFIRMED
CLASS:PUBLIC
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20200711T182813Z
LAST-MODIFIED:20200403T133525Z
DTSTART:20200406T183000Z
DTEND:20200406T193000Z
UID:event2324@bu.edu
URL:http://physics.bu.edu/events/show/2324
SUMMARY:Eco-evolutionary dynamics of microbial populations with heterogeneo
us growth and dispersal
DESCRIPTION:Featuring Ashish Bino George\, Boston University\, Physics Depa
rtment\n\nPart of the Departmental Seminars.\n\nUnderstanding eco-evolution
ary dynamics in bacterial colonies\, cancer tumors\, and the human\nmicrobi
ome is vital for many health\, energy\, and agricultural applications. Howe
ver\, spatial structure and population heterogeneity make this challenging.
My research examines the evolutionary consequences of cell shape asymmetry
and phenotypic heterogeneity in spatially expanding populations.\n\nFirst\
, I examine the evolutionary effect of chiral cell shape in bacterial\, hum
an\, and cancer cells. I will present a minimal model of chiral growth that
quantitatively reproduces experimental patterns in bacterial colonies. The
model shows that cells can invade by either increasing their chirality or
switching their handedness. To understand how chirality mediates competitio
n\, we derived a general effective theory of chiral growth. The theory reve
als that selection occurs due to coupling of the dynamics of the expanding
colony edge and the population dynamics at the edge.\n\nSecond\, I describe
a growing bacterial colony\, composed of phenotypes with distinct growth a
nd migration strategies. I show that coordinated phenotypic switching in a
cooperative population reproduces periodic\, pulsed expansions observed in
P. mirabilis colonies\, and discuss implied evolutionary tradeoffs. \nI con
clude by presenting ongoing work on the assembly of complex microbial commu
nities optimized to perform a specific function like producing biofuel or t
reating disease. I will describe a framework for community optimization and
methods to help bioengineers estimate the difficulty of searching for an o
ptimal community. \n\n\n\nJoin Zoom Meeting\nhttps://zoom.us/j/433892652\n\
nMeeting ID: 433 892 652
LOCATION: \, \,
STATUS:CONFIRMED
CLASS:PUBLIC
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20200711T182813Z
LAST-MODIFIED:20200407T181811Z
DTSTART:20200414T190000Z
DTEND:20200414T200000Z
UID:event2327@bu.edu
URL:http://physics.bu.edu/events/show/2327
SUMMARY:Scale-invariant neural dynamics for cognitive behavior
DESCRIPTION:Featuring Yue Liu\, Boston University\, Physics Department\n\nP
art of the Departmental Seminars.\n\nThe brain is operating in a world with
rich dynamics across a wide range of timescales\, therefore the collectiv
e activity of the large of number of neurons in the brain should reflect th
is multi-scale dynamics. Limited by experimental techniques and the nature
of laboratory behavior\, most established results in systems neuroscience c
oncern the short-term responses of single neurons to features in the world.
Recently\, new techniques for large-scale and chronic measurements of neur
al activity open up the opportunity to investigate neural dynamics across d
ifferent timescales. In this talk I will present modeling\, theoretical and
data analysis work on a particular type of temporal dynamics - scale-invar
iant dynamics - which has been implicated by both behavioral experiments an
d neural data. I will start with a neural circuit model that combines slow
intracellular calcium dynamics with the Post approximation of the inverse L
aplace transform to produce scale-invariant sequential neural activity and
point out evidence for the elements of the model in neural data. I will the
n present a theoretical analysis on the ability for a linear recurrent neur
al network to generate scale-invariant neural activity. I will show that th
e network connectivity matrix should have a geometric series of eigenvalues
and translated eigenvectors if the eigenvalues are real and distinct. Simi
lar but less compact results hold for matrices with complex or degenerate e
igenvalues. Finally I will show the existence of repeatable neural dynamics
on the timescale of minutes in multiple neural recordings of rodents perfo
rming various cognitive tasks. Taken together\, these results show that neu
ral activity has important dynamics over a much wider range of timescales t
hen previously thought\, and that the requirement for scale-invariance prov
ides interesting constraints for neural circuit models.\n\n\n-----\n\nZoom
Meeting\nhttps://bostonu.zoom.us/j/365061062\n\nMeeting ID: 365 061 062
LOCATION: \, \,
STATUS:CONFIRMED
CLASS:PUBLIC
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20200711T182813Z
LAST-MODIFIED:20200430T135627Z
DTSTART:20200430T193000Z
DTEND:20200430T203000Z
UID:event2335@bu.edu
URL:http://physics.bu.edu/events/show/2335
SUMMARY:The Zen of Neutrino: Neutrinoless Double Beta Decay and Deep Learni
ng
DESCRIPTION:Featuring Aobo Li\, Boston University\, Physics Department\n\nP
art of the Departmental Seminars.\n\nNeutrinoless Double Beta Decay (0Î½Î²Î
²) is a hypothetical lepton-number-violating process and it's existence is
one of the most important questions in particle physics. The discovery of 0
Î½Î²Î² would answer persistent questions related to the intrinsic nature of
neutrino mass and provide a window into physics beyond the Standard Model.
KamLAND-Zen is one of the world-leading efforts in the search of 0Î½Î²Î².
Data was recently collected with 735 kg of Xe-136 and analyzed using a freq
uentist likelihood analysis to set a limit on the 0Î½Î²Î² half-life. In add
ition to the well-established frequentist approach\, I conduct a Bayesian a
nalysis with a Markov Chain Monte Carlo (MCMC). The Bayesian approach allow
s the use modern statistical tools and serves as an important cross check o
f the frequentist analysis. Furthermore\, I developed a new machine learnin
g event classification algorithm to increase sensitivity to the 0Î½Î²Î² hal
f-life. In this talk\, I will present the Bayesian analysis framework and a
new result for the 0Î½Î²Î² half-life\, in addition to future improvements
with machine learning.\n\n-------\n\nJoin Zoom Meeting\nhttps://bostonu.zoo
m.us/j/7748832895\n\nMeeting ID: 774 883 2895
LOCATION: \, \,
STATUS:CONFIRMED
CLASS:PUBLIC
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20200711T182813Z
LAST-MODIFIED:20200608T200211Z
DTSTART:20200612T200000Z
DTEND:20200612T210000Z
UID:event2339@bu.edu
URL:http://physics.bu.edu/events/show/2339
SUMMARY:Persistent Dark States & Non-Ergodic Chaos in Anisotropic Central S
pin Models
DESCRIPTION:Featuring Tamiro Villazon Scholer\, Boston University\, Physics
Department\n\nPart of the Departmental Seminars.\n\nDark states\, in which
a qubit is effectively decoupled from its environment\, are pervasive in s
olid-state systems such as quantum dots and defect centers in diamond. In t
his seminar\, I will present recent work which establishes that dark states
are ubiquitous in a large class of inhomogeneous anisotropic central spin
models. These models have integrable limits with exact dark eigenstates in
which the central qubit is fully polarized. Remarkably\, dark states persis
t as eigenstates in the presence of strong integrability-breaking perturbat
ions\, and the qubit retains memory of its initial polarization. Although t
he eigenstates of the system are chaotic\, exhibiting exponential sensitivi
ty to small perturbations\, they do not satisfy the eigenstate thermalizati
on hypothesis. This chaotic but non-ergodic regime is found to be stable at
numerically accessible system sizes\, predicting long relaxation times tha
t increase exponentially with system size. I shall further discuss the impl
ications of these results in mesoscopic applications to dynamic nuclear pol
arization and quantum memory.\n\n\n\n------\n\n\nTopic: Departmental Semina
r - Tamiro Villazon \nTime: Jun 12\, 2020 03:45 PM Eastern Time (US and Can
ada)\n\nJoin Zoom Meeting\nhttps://bostonu.zoom.us/j/92960484899?pwd=UXBJSX
IzTUxubDBKL1hKTFY4RGczdz09\n\nMeeting ID: 929 6048 4899\n\nPassword: 455929
\n\nOne tap mobile\n\n+13126266799\,\,92960484899# US (Chicago)\n+164687699
23\,\,92960484899# US (New York)
LOCATION: \, \,
STATUS:CONFIRMED
CLASS:PUBLIC
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20200711T182813Z
LAST-MODIFIED:20200709T205211Z
DTSTART:20200730T200000Z
DTEND:20200730T210000Z
UID:event2349@bu.edu
URL:http://physics.bu.edu/events/show/2349
SUMMARY:Continuous Time Limit of the DTQW and Plasticity
DESCRIPTION:Featuring Michael Bahram Manighalam \, Boston University\, Phys
ics Department\n\nPart of the Departmental Seminars.\n\nA Plastic Quantum W
alk admits both continuous time and continuous spacetime. This model has be
en recently proposed\, leading to a general quantum simulation scheme for s
imulating fermions in the relativistic and non relativistic regimes. The ex
tension to two physical dimensions is still missing\, and in this seminar I
will present necessary and sufficient conditions concerning which discrete
time quantum walks can admit plasticity\, showing the resulting Hamiltonia
ns. I will consider coin operators as general 4 parameter unitary matrices\
, with parameters which are function of the lattice step size Îµ. This depe
ndence on Îµ encapsulates all functions of Îµ for which a Taylor series exp
ansion in Îµ is well defined\, making our results very general. \n\n---\n\n
Join Zoom Meeting\nhttps://bostonu.zoom.us/j/92238545183?pwd=eDBYL3VkVzByL2
JEOVZvcTA3d2ZhZz09\n\nMeeting ID: 922 3854 5183\nPassword: 913022
LOCATION: \, \,
STATUS:CONFIRMED
CLASS:PUBLIC
END:VEVENT
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