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BEGIN:VEVENT
SUMMARY:Comment on the Quantum Supremacy Claim by Google
DTSTART;VALUE=DATE-TIME:20210727T104500Z
DTEND;VALUE=DATE-TIME:20210727T110000Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7022@events.saip.org.za
DESCRIPTION:Speakers: Anirudh Reddy Segireddy (University of KwaZulu-natal
)\nThe recent paper by google [1] claiming to achieve quantum supremacy in
quantum computing has risen a lot of interest. While there seems to be lo
t of questions regarding the validity of their claims of achieving quantum
supremacy and comparison with the classical time frames in calculating th
e same quantity\, it seems that there is little doubt they indeed perform
computation using quantum operations. But the question still remains “af
ter operating the random quantum gates on the input state and making measu
rement\, with just the output data available\, how do we classify the data
as quantum or classical?” I.e\, The inputs sate has indeed has gone thr
ough a series of quantum operations (that operate on more than 2 qubits at
a time) to produce the available data. This due to the fact that the data
supporting supremacy is not verified. To address this question we propose
a modified verification scheme to test the output data which can tell us
whether data available is generated from a quantum computer or not along w
ith the fidelity and number of qubits in the quantum computer.\n \n \n \n
\n \nReferences:\n \n[1] Frank Arute etal. Quantum supremacy using a progr
ammable superconducting processor\, Nature\, Vol574\, 24 October 2019\, 50
5.\n\nhttps://events.saip.org.za/event/206/contributions/7022/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7022/
END:VEVENT
BEGIN:VEVENT
SUMMARY:An alternative test of Bell's theorem?
DTSTART;VALUE=DATE-TIME:20210727T103000Z
DTEND;VALUE=DATE-TIME:20210727T104500Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7023@events.saip.org.za
DESCRIPTION:Speakers: Thomas Konrad (UKZN)\nInspired by the dual correspon
dence between measurement and preparation procedures\, we discuss inequali
ties for observables of local realistic models which are violated accordin
g to the predictions of quantum mechanics\, thus demonstrating the inabili
ty of classical physics to reproduce all quantum predictions (Bell's theor
em). Such Bell inequalities test the statistical correlation between diffe
rent state preparations that lead to the same measurement result rather th
an vice versa as in previous Bell tests. The different perspective on quan
tum foundations leads to a new QKD protocol and hopefully paves the way to
other applications of quantum mechanics.\n\nhttps://events.saip.org.za/ev
ent/206/contributions/7023/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7023/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum Entanglement and relativistic quantum mechanics.
DTSTART;VALUE=DATE-TIME:20210727T101500Z
DTEND;VALUE=DATE-TIME:20210727T103000Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7024@events.saip.org.za
DESCRIPTION:Speakers: Jonathan Hartman (University of Johannesburg)\nPrevi
ously\, we have discussed Bell correlations in a relativistic setting and
the possibility of using these to detect weak forces between particles. No
w a theoretical description of quantum entanglement in terms of relativist
ic quantum mechanics is presented. Essentially\, in non-relativistic quant
um mechanics\, entanglement leads to a non-local correlation between 2 par
ticles. This was shown by John Bell in 1964 when he derived an inequality
that should hold for all possible correlations that could be described by
classical local realism. However\, it turns out that the predictions of qu
antum mechanics can violate this inequality and these predictions have sub
sequently been confirmed experimentally\, hence these correlations must be
non-local. Bell’s original calculation was only done for non-relativist
ic quantum mechanics but there have been some recent authors who have trie
d to do the calculation for relativistic quantum mechanics. What they have
found is that the Bell correlations in relativistic quantum mechanics are
altered slightly from the non-relativistic case. For example\, the measur
ement of the Bell correlations from a lab frame in a Lorentz boost perpend
icular to the centre of momentum frame produces a correlation that differs
from the maximum violation by the Wigner angle (i.e. the angle produced b
y combining 2 Lorentz boosts in special relativity). While at first sight\
, it appears as the the correlation is weakened\, one can in fact recover
the maximal violation of the Bell inequality by adjusting the directions o
f measurement relative to each other by this Wigner angle. So in fact\, th
e maximal violation of Bell’s inequality is preserved but in different d
irections. This effect was the centrepiece of our previous work published
in SAIP conference proceedings because we showed that if there were accele
rations between the entangled particles (probably due to forces between th
e particles)\, it could potentially produce a measurable effect. Now we’
re putting this work on a more theoretical footing\, by calculating the ef
fect in the language of relativistic quantum mechanics by making use of Di
rac spinors and the Schwinger-Tomonaga equation.\n\nhttps://events.saip.or
g.za/event/206/contributions/7024/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7024/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quasinormal modes in the large angular momentum limit: an inverse
multipolar expansion analysis
DTSTART;VALUE=DATE-TIME:20210727T100000Z
DTEND;VALUE=DATE-TIME:20210727T101500Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7004@events.saip.org.za
DESCRIPTION:Speakers: Anna Chrysostomou (University of Johannesburg)\nThe
quasinormal modes (QNMs) of a black hole (BH) may be identified as a class
of damped\, classical oscillations in spacetime\, emergent as part of the
late-stage response to a perturbation of the compact body. In the weak-fi
eld limit\, the radial behaviour of these oscillations can be modelled as
a wave equation whose potential varies to represent different fields. The
choice of computational method applied to solve these QNMs must accommodat
e the specifics of the BH spacetime and wave equation dependencies\, as a
certain approach may fail under conditions where another proves more accur
ate. Through a novel exploitation of the null geodesics of spherically-sym
metric BHs\, Dolan and Ottewill recently constructed an inverse multipolar
expansion method that allows for the efficient computation of BH quasinor
mal frequencies (QNFs). In a previous work\, we have seen that this method
is well suited to the exploration of the large angular momentum regime of
QNFs of various spin for Schwarzschild\, Reissner-Nordström\, and Schwar
zschild de Sitter BHs. Here\, we extend this method to the computation of
the QNM wavefunctions within a Schwarzschild BH spacetime\, and subject th
e resulting expressions to the asymptotic limit of $\\ell \\rightarrow \\i
nfty$.\n\nhttps://events.saip.org.za/event/206/contributions/7004/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7004/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bianchi Type V Model In R^n Gravity: A Dynamical System Approach
DTSTART;VALUE=DATE-TIME:20210727T094500Z
DTEND;VALUE=DATE-TIME:20210727T100000Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7016@events.saip.org.za
DESCRIPTION:Speakers: Thato Tsabone (North-West University)\nThe accelerat
ed expansion of the universe and the rotational dynamics of galaxies have
become part of the mysteries of the physical world and have had theorists
working tirelessy for the past years. There is no consensus on what is cau
sing these observable effects: whether it is the the unknown dark energy a
nd dark matter or it is the breaking down of our currently accepted theory
of gravity\, General Relativity\, at larger scales. In this work we study
the dynamics of a cosmological model described by the Bianchi Type V spac
etime in f(R) gravity using the dynamical system analysis. We derive the f
ield equations for a general Bianchi model in the context of f(R) gravity
using the tetrad formalism and then specialize in the Type V model. Qualit
ative description and exact solutions are given for f(R) = R (General Rela
tivity) and for f(R) = R^n. We find no accelerating solutions in the case
of General Relativity with an exception when darkn energy is considered wh
ere we find one accelerating solution. In the case of Rn-gravity we find 2
possible accelerating solutions depending on the value of n.\n\nhttps://e
vents.saip.org.za/event/206/contributions/7016/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7016/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cosmological Models in Gravitational Scalar-Tensor Theories
DTSTART;VALUE=DATE-TIME:20210727T093000Z
DTEND;VALUE=DATE-TIME:20210727T094500Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7029@events.saip.org.za
DESCRIPTION:Speakers: Heba Abdulrahman (North West University\, South Afri
ca)\nIn this work\, a brief review of a new form of scalar-tensor theories
of gravity\, known as gravitational scalar-tensor theories (GST) in which
the action is composed of the Ricci scalar and its first and second deriv
atives is made. Some of the cosmological applications that have been inves
tigated in these new theories are discussed considering different models c
orresponding to the first non-trivial extensions of general relativity pos
sessing 2 + 2 degrees of freedom. We show that the resulting cosmological
behavior is in agreement with observations.\n\nhttps://events.saip.org.za/
event/206/contributions/7029/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7029/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Random Number Generation using IBM Quantum Processors
DTSTART;VALUE=DATE-TIME:20210726T141500Z
DTEND;VALUE=DATE-TIME:20210726T143000Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7012@events.saip.org.za
DESCRIPTION:Speakers: Conrad Strydom (Stellenbosch University)\nRandom num
bers are used extensively in both cryptography and simulation\, but are di
fficult to generate reliably using classical methods. We investigate rando
m number generation on the ibmq_16_melbourne quantum processor\, a 15-qubi
t superconducting quantum computer. By applying simple post-processing tec
hniques to the random bits generated\, we were able to extract a sample of
random bits which passed the NIST Statistical Test Suite. This shows that
\, with some post-processing\, solid-state quantum computers such as IBM q
uantum processors can be used to generate random numbers of sufficient qua
lity for cryptographic applications.\n\nhttps://events.saip.org.za/event/2
06/contributions/7012/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7012/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Constraints on Dark Matter Models using current LHC Measurements
DTSTART;VALUE=DATE-TIME:20210726T140000Z
DTEND;VALUE=DATE-TIME:20210726T141500Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7008@events.saip.org.za
DESCRIPTION:Speakers: Danielle Wilson (University of the Witwatersrand)\nI
n an era where high energy particle physics is having to transition from a
theory-driven to a data-driven approach\, the traditional method of perfo
rming specific searches off of theory models may be inefficient. Contur (C
onstraints On New Theories Using Rivet) was designed as a means to quickly
exclude BSM models based off the many LHC measurements currently containe
d in Rivet. Focusing on track based measurements\, the sensitivity of Cont
ur to some Dark Matter models was explored. The exclusion potential of sof
t unclustered energy patterns (SUEP) and different dark sector jets scenar
ios will be presented.\n\nhttps://events.saip.org.za/event/206/contributio
ns/7008/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7008/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Towards discrimination and improved modelling of dark-sector showe
rs
DTSTART;VALUE=DATE-TIME:20210726T134500Z
DTEND;VALUE=DATE-TIME:20210726T140000Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7007@events.saip.org.za
DESCRIPTION:Speakers: Sukanya Sinha (The University of Witwatersrand)\nOne
of the biggest problems in particle physics today\, is understanding the
nature of dark matter. If dark mesons exist\, their evolution and hadroniz
ation procedure are currently little constrained. They could decay promptl
y and result in a very SM QCD like jet structure\, even though the origina
l decaying particles are dark sector ones\; they could behave as semi-visi
ble jets\; or they could behave as completely detector-stable hadrons\, in
which case the final state is just the missing transverse momentum. In a
recent work\, we have shown that the dark sector can potentially be probed
with jet-substructure observables\, however\, the modelling of these scen
arios is somewhat an unexplored area\, owing to the existence of only Pyth
ia Hidden Valley dark shower module. An alternate dark shower model is bec
oming more necessary\, in order to gauge the theory systematics and the ex
tent of model dependence. In this talk\, I will cover the proposed idea of
having a Herwig hidden valley dark shower and hadronisation module\, as w
ell as our published work on jet-substructure studies for semi-visible je
ts.\n\nhttps://events.saip.org.za/event/206/contributions/7007/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7007/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fitting the relic density with contributions from dimension-five o
perators
DTSTART;VALUE=DATE-TIME:20210726T133000Z
DTEND;VALUE=DATE-TIME:20210726T134500Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7003@events.saip.org.za
DESCRIPTION:Speakers: Lara Mason (University of Johannesburg)\nWe study th
e relic density and astrophysical constraints of an effective model featur
ing top-philic scalar dark matter and a heavy T-channel mediator. The addi
tion of a dimension-five contact term which is common to BSM scenarios mod
ifies the available parameter space\, and the model features interplay bet
ween the associated Wilson coefficient and Yukawa parameter in producing t
he correct relic density. We present an analytical fit to the relic densit
y\, considering co-annihilations when relevant\, and discuss the detection
constraints.\n\nhttps://events.saip.org.za/event/206/contributions/7003/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7003/
END:VEVENT
BEGIN:VEVENT
SUMMARY:B and D meson Suppression and Azimuthal Anisotropy in a Strongly C
oupled Plasma at $\\sqrt{s_{NN}}=5.5$ TeV
DTSTART;VALUE=DATE-TIME:20210726T131500Z
DTEND;VALUE=DATE-TIME:20210726T133000Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7025@events.saip.org.za
DESCRIPTION:Speakers: Blessed Ngwenya (University of Cape Town)\nWe presen
t predictions for the suppression and angular distribution of B and D meso
ns in $\\sqrt{s}=5.5$ TeV Pb+Pb collisions at the LHC for central\, semi-c
entral and peripheral collisions. Ultrarelativistic heavy-ion collisions p
roduce an enormous amount of energy\, resulting in the formation of a quar
k-gluon plasma (QGP). Studying the behaviour of particles (e.g. heavy quar
ks) propagating through the QGP enables us to probe the physics of the QGP
and the many-body dynamics of QCD. B and D mesons are the decay products
of heavy quarks i.e. bottom and charm respectively and their large mass i
mplies that they are produced very early in the collision and act as ideal
probes\, since they navigate the whole evolution of the QGP medium. The s
uppression of heavy mesons is a result of interactions with the produced Q
GP medium and the angular distribution is due to the initial geometric asy
mmetry during the collision. These heavy flavour energy loss studies are c
rucial for understanding the properties of nuclear matter and we provide t
hese predictions for comparison to future LHC measurements.\n\nhttps://eve
nts.saip.org.za/event/206/contributions/7025/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7025/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Factorization in Heavy Ion Collisions
DTSTART;VALUE=DATE-TIME:20210726T130000Z
DTEND;VALUE=DATE-TIME:20210726T131500Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7027@events.saip.org.za
DESCRIPTION:Speakers: William Horowitz (University of Cape Town)\nWe prese
nt our latest findings on the status of factorization in heavy ion collisi
ons. In the first microsecond of the universe\, space was filled with dec
onfined nuclear matter at a temperature of a trillion degrees. These cond
itions are recreated thousands of times a second at experiments in the US
and Europe in which large nuclei such as gold and lead are collided at nea
rly the speed of light. Very high momentum particles that propagate throu
gh the fireballs generated in these heavy ion collisions form one of the e
ssential probes of the properties of the quark-gluon plasma (QGP) that per
meated the early universe. In order for these high momentum particles to
be a well-calibrated probe\, we must ensure that the quantitative predicti
ons for their behavior are well-controlled. The rigorous language for thi
s control is known as factorization\, which implies that the production an
d hadronization processes are independent of the interaction of the probe
with the QGP medium. We show how previous energy loss calculations diagra
mmatically fail at factorization and point to a way forward for future pro
gress.\n\nhttps://events.saip.org.za/event/206/contributions/7027/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7027/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Motor Protein Transport on Cytoskeleton Networks
DTSTART;VALUE=DATE-TIME:20210726T104500Z
DTEND;VALUE=DATE-TIME:20210726T110000Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7013@events.saip.org.za
DESCRIPTION:Speakers: Nadine Dempers (Department of Physics\, Stellenbosch
University and National Institute of Theoretical Physics)\nMolecular mach
ines\, known as motor proteins\, walk along configurations of filamentous
proteins which make up the cytoskeleton of a cell. These motor proteins\,
for example kinesins\, are responsible for transporting a variety of cargo
es within the cell. The arrival of the cargoes at specific locations withi
n the cell are imperative for the successful execution of various cellular
processes\, including cell division. Although much detail is known about
the different proteins that are able to transport certain cargoes\, the ex
act processes that influence the distribution of these cargoes throughout
the cell are still unclear. Whilst theoretical models may provide further
insights into intracellular processes\, there is an absence of such model
s describing the dynamics and diffusion of motor proteins throughout the i
nterior of cells. In light of this\, the aim of this talk is to explore po
ssibilities for analytical modelling of the motion of motor proteins withi
n the context of a cell. To begin this exploration\, the Langevin dynamics
of a single motor protein transporting a cargo as it progresses along dif
ferent configurations of a single filament will be considered. The mathe
matical challenge posed by modelling this process in a similar manner for
more intricate filament configurations will then be addressed through a co
mbination of a dynamical field theoretical formalism with a networking the
ory employed in polymer physics (see e.g. [1]). The talk will be conclude
d with a glimpse of how the formalism may allow for the extension of the m
odel to describe transport over a density of filaments that one might expe
ct to find within a cell. \n\n\n[1] S. F. Edwards\, “A field theory form
ulation of polymer networks\,” J. Phys. Fr.\, vol. 49\,\npp. 1673–1682
\, 1988.\n\nhttps://events.saip.org.za/event/206/contributions/7013/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7013/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Solving the Schrödinger equation for Hydrogen Molecular ion (H2+)
using Sinc functions and empolying both Python and Numpy
DTSTART;VALUE=DATE-TIME:20210726T103000Z
DTEND;VALUE=DATE-TIME:20210726T104500Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7006@events.saip.org.za
DESCRIPTION:Speakers: OBIAGELI LOVENDA EZENWACHUKWU (UNIVERSITY OF SOUTH A
FRICA (UNISA))\nIn this contribution\, we present the results of calculati
ons for the ground state energy of H2+ employing Sinc functions as a basis
set as discussed for a number of\nexamples in [1]. The modifications requ
ired to the basis functions to make them suitable for calculating the grou
nd state energy of H2+ as well as the application of the cusp factor formu
lism [2] are outlined. Finally the resulting energies are investigated as
a function of the number of basis functions and double-logarithmic fits ar
e performed. It is found that they converge with an order of at least six.
\n[1] Proceedings of 64th SAIP Conference 2019\, ISBN: 978-0-620-88875-2\
, edited by Prof. Makaiko Chithambo\, p 347\n[2] Eur. Phys. J. B. (2019) 9
2: 230\n\nhttps://events.saip.org.za/event/206/contributions/7006/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7006/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Three-party reference frame independent quantum key distribution w
ith an imperfect source
DTSTART;VALUE=DATE-TIME:20210726T101500Z
DTEND;VALUE=DATE-TIME:20210726T103000Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7021@events.saip.org.za
DESCRIPTION:Speakers: Comfort Sekga (Department of Physics and Astronomy\,
Botswana International University fo Science and Technology\, Private Bag
16 Palapye\, Botswana)\nTraditionally\, quantum key distribution (QKD) is
used for sharing secret key between two distant authorized participants w
ith unconditional security. Here\, we extend the reach of QKD by proposing
a reference frame independent quantum key distribution (RFI-QKD) which al
lows three legitimate parties to share the common secret keys without any
alignment of reference frames in their quantum channels. Furthermore\, we
relax the assumption of perfect state preparation by employing loss tolera
nt technique proposed by Tamaki et al. [Phys. Rev. A 90\, 052314 (2014)]
in our security proof\, which makes the proposed protocol suitable for pra
ctical applications. In addition\, we derive bounds of the proposed RFI-QK
D protocol by considering ﬁnite-size key security analysis against gener
al attacks in the presence of statistical ﬂuctuations. The simulation re
sults show that the performance of RFI-QKD with an imperfect source is com
parable to that of RFI-QKD with a perfect source. Also\, we investigated t
he impact of reference frame misalignment on the stability of our protocol
for drifting of reference frames by angles 𝛽 = 𝜋/4\, 𝜋/6 and
𝛽 = 𝜋/8. Remarkably\, our results demonstrate that our proposed prot
ocol is not heavily aﬀected by an increase in misalignment of reference
frames as the achievable transmission distances are still comparable to th
e case where there is no misalignment in reference frames (when 𝛽 = 0).
The proposed protocol has immediate application in quantum network scena
rios such as web conferences and online courses\, where there are more tha
n two users who need to share keys.\n\nhttps://events.saip.org.za/event/20
6/contributions/7021/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7021/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Imaging with moving detectors
DTSTART;VALUE=DATE-TIME:20210726T100000Z
DTEND;VALUE=DATE-TIME:20210726T101500Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7033@events.saip.org.za
DESCRIPTION:Speakers: Nicholas Bornman (University of the Witwatersrand)\n
The theoretical framework behind modern-day quantum optics has been succes
sful in explaining a number of interesting phenomena. However\, since it i
s traditionally formulated using ordinary quantum mechanics and Fourier op
tics\, it cannot account for relativistic notions such as different refere
nce frames (including non-inertial ones) or curved classical gravitational
backgrounds. In an attempt to understand the quantum imaging process with
in a more complete quantum field theory (QFT) framework\, a novel analogy
is proposed: so-called Unruh-DeWitt (UDW) detectors can be used to model b
oth the object one wishes to image as well as the pixelated imaging device
itself. As an example\, after coupling a QFT version of a biphoton state
created via spontaneous parametric down-conversion (which is one of the pr
incipal processes used to create entangled photons in the laboratory) with
arrays of Unruh-DeWitt detectors\, we investigate quantum ghost imaging u
nder both inertial and accelerating conditions. Given that the reconstruct
ed images can be discerned better than a pure guess\, the formalism appear
s capable of describing the quantum imaging process in non-trivial referen
ce frames.\n\nhttps://events.saip.org.za/event/206/contributions/7033/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7033/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Generation of GHZ states via projected squeezed states
DTSTART;VALUE=DATE-TIME:20210726T094500Z
DTEND;VALUE=DATE-TIME:20210726T100000Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7009@events.saip.org.za
DESCRIPTION:Speakers: Byron Alexander (Stellenbosch University)\nEmerging
quantum technologies rely principally on quantum phenomena such as superpo
sition and entanglement for their unique capabilities. To this end\, it is
essential to develop well-defined and efficient protocols to produce and
further exercise control over states of quantum bits that exhibit desired
quantum mechanical traits. From a pure separable multipartite state\, a co
ntrol sequence\, which includes rotation\, spin squeezing via one-axis twi
sting\, quantum measurement and post-selection\, generates a highly entang
led multipartite state\, which we refer to as a *Projected Squeezed* ($PS$
) state. Through an optimization method\, we then identify parameters req
uired to maximize the overlap fidelity of the $PS$ state with the maximall
y entangled Greenberger-Horne-Zeilinger ($GHZ$) state. The method leads to
an appreciable decrease in the state preparation time of $n$-qubit $GHZ$
states when compared to preparation through unitary evolution. The efficie
ncy of the $PS$ state protocol is studied in non-ideal experimentally rele
vant settings by simulating decoherence channels using numerical methods.\
n\nhttps://events.saip.org.za/event/206/contributions/7009/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7009/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Generating function approach to open quantum walks
DTSTART;VALUE=DATE-TIME:20210726T093000Z
DTEND;VALUE=DATE-TIME:20210726T094500Z
DTSTAMP;VALUE=DATE-TIME:20240913T182517Z
UID:indico-contribution-420-7005@events.saip.org.za
DESCRIPTION:Speakers: Ayanda Zungu (Department of Physics\, North-West Uni
versity\, Mafikeng Campus)\nOpen quantum walks (OQWs) have been introduced
as a type of quantum walks which are entirely driven by the dissipative i
nteraction with external environments and are defined in terms of discrete
completely positive trace-preserving maps on graphs [1]. Recently\, a qua
ntum optical scheme for the experimental realization of OQWs was proposed
[2]. In the proposed scheme\, a two-level atom plays the role of the "walk
er" and the Fock states of the cavity mode correspond to the lattice sites
of the OQW. Using the small unitary rotations approach and rotating wave
approximation the effective dynamics of the system is shown to be an OQW.
The presence of spontaneous emission in the system was an essential ingred
ient for obtaining an OQW. In this contribution\, we solve this OQW analyt
ically using generating functions. We used the obtained solution to constr
uct the moments of this quantum walk explicitly. The dynamics of the obser
vables (mean\, variance) are presented for various parameters.\n\nKeywords
: Open quantum walks\; quantum optics\; quantum dynamics engineering.\n\nR
eferences:\n \n[1] S. Attal\, F. Petruccione\, C. Sabot and I. Sinayskiy\,
J. Stat. Phys. 147 (2012)\, 832.\n[2] I. Sinayskiy and F. Petruccione\, I
nt. J. Quantum Inform. 12 (2014)\, 1461010.\n\nhttps://events.saip.org.za/
event/206/contributions/7005/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7005/
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