BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:G. Mazzola - Applications for the noisy and intermediate scale era
of quantum computing (part 1)
DTSTART;VALUE=DATE-TIME:20190918T070000Z
DTEND;VALUE=DATE-TIME:20190918T083000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-183@cern.ch
DESCRIPTION:I review the most promising quantum algorithms and application
s suitable for existing and near futures devices. I present results concer
ning proof-of-principle calculations on IBM hardwares ranging from combina
torial optimization (e.g. protein folding)\, electronic structure (e.g. ch
emistry and condensed matter)\, and sampling (useful for financial applica
tions).\n\nhttps://indico.unina.it/event/24/contributions/183/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/183/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A. Mezzacapo - Loading and solving fermionic problems on quantum c
omputers
DTSTART;VALUE=DATE-TIME:20190919T161000Z
DTEND;VALUE=DATE-TIME:20190919T174000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-190@cern.ch
DESCRIPTION:We show how to express fermionic problems in qubit language\,
exploring\ndifferent techniques. We then expose the limitations of current
state\nof the art quantum computers in solving correlated fermionic syste
ms\nsuch as molecular models.\n\nhttps://indico.unina.it/event/24/contribu
tions/190/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/190/
END:VEVENT
BEGIN:VEVENT
SUMMARY:closing
DTSTART;VALUE=DATE-TIME:20190921T103000Z
DTEND;VALUE=DATE-TIME:20190921T110000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-197@cern.ch
DESCRIPTION:https://indico.unina.it/event/24/contributions/197/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/197/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A. Mezzacapo - Querying quantum computers via neural network
DTSTART;VALUE=DATE-TIME:20190920T160000Z
DTEND;VALUE=DATE-TIME:20190920T173000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-194@cern.ch
DESCRIPTION:We show how the use of neural networks can help augmenting the
\nprecision of observables estimation on a quantum computer\, addressing\n
one of the main challenges of short-depth algorithms.\n\nhttps://indico.un
ina.it/event/24/contributions/194/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/194/
END:VEVENT
BEGIN:VEVENT
SUMMARY:welcome
DTSTART;VALUE=DATE-TIME:20190916T063000Z
DTEND;VALUE=DATE-TIME:20190916T065500Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-174@cern.ch
DESCRIPTION:https://indico.unina.it/event/24/contributions/174/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/174/
END:VEVENT
BEGIN:VEVENT
SUMMARY:arrival and registration
DTSTART;VALUE=DATE-TIME:20190915T160000Z
DTEND;VALUE=DATE-TIME:20190915T173000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-173@cern.ch
DESCRIPTION:https://indico.unina.it/event/24/contributions/173/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/173/
END:VEVENT
BEGIN:VEVENT
SUMMARY:S. Pilati - Adiabatic quantum computing and simulated quantum anne
aling (part 1)
DTSTART;VALUE=DATE-TIME:20190916T090000Z
DTEND;VALUE=DATE-TIME:20190916T103000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-176@cern.ch
DESCRIPTION:I will introduce some elements of adiabatic quantum computing\
, with special focus on approaches that aim to solve hard combinatorial op
timization problems via quantum annealing. The main features of currently
commercialized quantum annealing devices will be described.\nI will provid
e some notions concerning quantum Monte Carlo algorithms and discuss how t
hese simulation techniques are being use as a benchmark for quantum anneal
ers and as a tool to inspect if and when a quantum quantum annealing devic
es might display a quantum speed-up compared to classical optimization met
hods.\n\nhttps://indico.unina.it/event/24/contributions/176/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/176/
END:VEVENT
BEGIN:VEVENT
SUMMARY:F. Cataliotti - soft skills (part 2)
DTSTART;VALUE=DATE-TIME:20190917T161000Z
DTEND;VALUE=DATE-TIME:20190917T174000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-182@cern.ch
DESCRIPTION:https://indico.unina.it/event/24/contributions/182/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/182/
END:VEVENT
BEGIN:VEVENT
SUMMARY:F. Cataliotti - soft skills (part 1)
DTSTART;VALUE=DATE-TIME:20190917T090000Z
DTEND;VALUE=DATE-TIME:20190917T103000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-178@cern.ch
DESCRIPTION:https://indico.unina.it/event/24/contributions/178/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/178/
END:VEVENT
BEGIN:VEVENT
SUMMARY:F. Scazza - Ultracold atomic Fermi gases in the strongly correlate
d regime (part 2)
DTSTART;VALUE=DATE-TIME:20190919T090000Z
DTEND;VALUE=DATE-TIME:20190919T103000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-188@cern.ch
DESCRIPTION:Ultracold atomic gases provide a formidable platform for quant
um simulation of a variety of models initially introduced in condensed mat
ter physics or other areas. One of the most promising applications of quan
tum simulation is the study of strongly correlated Fermi gases\, for which
accurate theoretical predictions are challenging even with state-of-the-a
rt approaches. In this lecture\, I will first briefly review the foundatio
ns of atom-light interactions and explain how these are exploited to cool\
, trap and manipulate atoms. I will then introduce ultracold atomic Fermi
gases\, from the non-interacting case to the famous strongly correlated BE
C-BCS crossover. I will also describe some recent experiments\, highlighti
ng the unique and fascinating aspects of crossover superfluids. In the sec
ond part of the lecture\, I will present a general introduction to the Fer
mi-Hubbard model and outline its realization with ultracold fermions in op
tical lattices\, highlighting the foremost experimental achievements so fa
r. To conclude\, I will shortly discuss some novel approaches to quantum s
imulation of quantum magnetism and long-range interacting systems.\n\nhttp
s://indico.unina.it/event/24/contributions/188/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/188/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pratibha Raghupati Hegde - An evolutionary strategy for finding ef
fective quantum 2-body Hamiltonians of p-body interacting systems
DTSTART;VALUE=DATE-TIME:20190917T155000Z
DTEND;VALUE=DATE-TIME:20190917T161000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-286@cern.ch
DESCRIPTION:Quantum annealing can be used to solve optimization prob-\nlem
s. Quantum processors\, performing quantum annealing\, operate mini-\nmizi
ng a cost function. The central issue is to map the cost function which\nh
as p-body interactions into a function with at most 2-body interactions.\n
In the already existing method of minor embedding\, xing the number of\nan
cillae qubits for highly interacting models becomes impractical. Here\nwe
propose a technique for obtaining approximate mapping based on ge-\nnetic
algorithms. We verify the feasibility of this procedure by mapping\nferrom
agnetic p-spin model in two analytically solvable cases.\n\nBased on the m
anuscript submitted to the journal of Quantum Machine Intelligence-\nPassa
relli\, G. et. al\, An evolutionary strategy for nding eective quantum 2-b
ody\nHamiltonians of p-body interacting systems.\n\nhttps://indico.unina.i
t/event/24/contributions/286/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/286/
END:VEVENT
BEGIN:VEVENT
SUMMARY:D. Esteve - From Dynamical Coulomb Blockade in Josephson Junctions
to Non-Classical Microwave Sources
DTSTART;VALUE=DATE-TIME:20190919T070000Z
DTEND;VALUE=DATE-TIME:20190919T083000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-187@cern.ch
DESCRIPTION:This lecture considers a Josephson junction in series with an
impedance voltage biased below the gap. In this simple quantum electrodyna
mics system\, the coupling constant between Cooper pair tunneling and each
mode of the impedance is determined by the ratio between the mode impedan
ce Z=√(L/C) and the relevant resistance quantum RQ= h/(2e)2 ~6.5 kOhms.
A series of interesting situations that have been investigated will be con
sidered in this lecture.\nIn the simplest case of a single mode resonator\
, the transfer of a single Cooper pair only occurs when its energy 2eV can
be transformed in 1\,2\,..n photonic excitations in the resonator. This i
nelastic tunneling phenomenon is the essence of Dynamical Coulomb Blockade
. In the strong coupling regime\, the presence of a single photon can even
block the creation of a second one\, which forces the resonator to emit a
single photon in the external circuit before another Cooper pair can pass
and re-excite it. One gets this way a very simple single photon source.\n
In a two-mode resonator circuit with different frequencies\, the transfer
of a single Cooper pair can simultaneously excite a single photonic excita
tion in each mode. The photons leaking out of the resonators in the measur
ement lines are then entangled. In the particular case of two resonators r
espectively with a high (low) Q\, the stabilization of a single excitation
Fock state in the high Q resonator can furthermore be achieved.\nApplicat
ions are sought for these non-classical sources of radiation in the microw
ave domain that could be extended up to the THz frequency range.\n\nhttps:
//indico.unina.it/event/24/contributions/187/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/187/
END:VEVENT
BEGIN:VEVENT
SUMMARY:V. Gebhart - Quantifying speedup in Grover’s search algorithm by
multipartite entanglement
DTSTART;VALUE=DATE-TIME:20190918T135000Z
DTEND;VALUE=DATE-TIME:20190918T141000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-292@cern.ch
DESCRIPTION:We discuss the intimate connection between the quantum speedup
of the (pseudo-)pure state Grover algorithm and the detection of multipar
tite entanglement using the Quantum Fisher Information (QFI). The quantum
speedup is proportional to the maximal QFI during the algorithm\, and henc
e proportional to the thereby detected k-partite entanglement. For small p
urities\, speed-up still persists even though no entanglement is detected\
, however\, the QFI still remains a quanfitier of the speed-up.\n\nhttps:/
/indico.unina.it/event/24/contributions/292/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/292/
END:VEVENT
BEGIN:VEVENT
SUMMARY:D. Esteve - Superconducting Quantum Bits and Hybrid Spin Supercond
ucting Circuits for Quantum Technologies
DTSTART;VALUE=DATE-TIME:20190920T070000Z
DTEND;VALUE=DATE-TIME:20190920T083000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-191@cern.ch
DESCRIPTION:In the domain of electrical circuits\, superconducting quantum
bits based on Josephson junctions are presently the most advanced qubits.
I will describe the single Cooper pair box circuit\, its transmon version
used nowadays\, and the operation of an elementary quantum processor. I w
ill explain the scalability challenge required by quantum error correction
\, and the alternative routes for facing it. We are developing such an alt
ernative hybrid route based on spins with superior quantum coherence coupl
ed to quantum superconducting circuits. I will present the progress achiev
ed in the control of a small number of electronic spins for performing ult
ra-sensitive Electronic Spin Resonance\, and the perspectives open for qua
ntum information processing.\n\nhttps://indico.unina.it/event/24/contribut
ions/191/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/191/
END:VEVENT
BEGIN:VEVENT
SUMMARY:S. Poletto - Engineering superconducting transmon qubits (part 2)
DTSTART;VALUE=DATE-TIME:20190920T090000Z
DTEND;VALUE=DATE-TIME:20190920T103000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-192@cern.ch
DESCRIPTION:In this series of lectures I will describe how superconducting
transmon\nqubits are engineered\, designed\, and fabricated.\n\nI start i
ntroducing the building blocks of superconducting quantum\nprocessors from
an engineering point of view\, with a focus on working\nparameters and de
sign considerations. I will emphasize similarities with\nstandard microwav
e engineer elements such as transmission lines\,\nresonators\, and capacit
ive or inductive couplings.\n\nI will provide a deep insight on how the wo
rking parameters of the quantum\nprocessor are linked to the performances
of the device and to the lifetime\nof the qubits.\n\nI will conclude with
an overview of the common fabrication techniques to\nproduce superconducti
ng quantum processors.\n\nAt the end of this series of lectures the audien
ce will be familiar with\nequations and tools used to engineer superconduc
ting transmon quantum\nprocessors. Moreover\, they will know how to balanc
e the tradeoff between\nperformances and coherence times imposed at the de
sign stage.\n\nhttps://indico.unina.it/event/24/contributions/192/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/192/
END:VEVENT
BEGIN:VEVENT
SUMMARY:V. Piselli - Study of the Josephson current along the BCS side of
the BSC-BEC crossover
DTSTART;VALUE=DATE-TIME:20190918T154000Z
DTEND;VALUE=DATE-TIME:20190918T160000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-296@cern.ch
DESCRIPTION:Since its theoretical prediction in 1962 [1]\, the tunnelling
current (with no applied voltage) that arises in a system constituted by t
wo superconductors separated by a barrier has been the subject of many sci
entific studies. It was quite soon discovered that the current-phase relat
ion I=ICsin(ϕ) (where ϕ is the phase difference between the order parame
ter of the two superconductors) as predicted in [1] does not always apply\
, depending both on the temperature and the barrier of the system. As a ma
tter of fact\, quite different types of current-phase relation can be foun
d using as the separating barrier either insulators\, normal metals\, and
superconductors\, or more general constrictions of different heights and w
idths both in condensed matter and in ultra-cold atoms experiments.\n\nIn
order to better understand the mechanism at the basis of the DC Josephson
effect and to model both the current-phase relation and the critical value
IC\, several theoretical and numerical approaches have been developed. Th
e early works relied mostly on the Ginzburg-Landau equations [2][3][4][5][
6]\, but there were also attempts to use microscopic theories [7][8][9] or
perturbative calculations [10]. More recently methods have been developed
based on the quasi-classical Green’s functions [11][12] and the Bogoliu
bov-deGennes (BdG) equations [13][14].\nDespite some good agreements with
the experimental data [15][11][12]\, none of these approaches could be suc
cessfully applied to the following circumstances of physical interest:\n\n
over the whole temperature range from T=0 to T=Tc\;\n to all possib
le barrier widths and heights\;\n along (most part of) the BCS-BEC cros
sover.\n\nThe main reason underlying of our study of the DC Josephson effe
ct has been to fill this gap. To this end\, we have made use of a local-ph
ase-density approximation to the BdG equations\, both in its local (LPDA)
[16] and non-local (NLPDA) [17] versions. Both LPDA and NLPDA approaches\,
which are computationally faster and less storage demanding than the BdG
equations\, give us the opportunity to study the behavior of the Josephson
current with reliable results along the BCS side of the BCS-BEC crossover
\, with no limitations on the barrier width and down to low temperatures.\
n\nREFERENCES:\n\n[1] B.D. Josephson. Possible new effects in superconduct
ive tunnelling.\nPhysics letters\, 1(7):251–253\, 1962.\n\n[2] P. De Gen
nes. Self-consistent calculation of the josephson current. Phys.\nletters\
, 5\, 1963.\n\n[3] P. de Gennes. Boundary effects in superconductors. Revi
ews of Modern\nPhysics\, 36(1):225\, 1964.\n\n[4] H.J. Fink. Supercurrents
through superconducting-normal-superconducting\nproximity layers. i. anal
ytic solution. Physical Review B\, 14(3):1028\, 1976.\n\n[5] H.J. Fink and
RS Poulsen. Supercurrents through proximity layers. ii. numeri-\ncal solu
tion of superconducting-normal-superconducting and superconducting-\nsuper
conducting-superconducting weak links. Physical Review B\, 19(11):5716\,\n
1979.\n\n[6] A. Baratoff\, J.A. Blackburn\, and Brian B Schwartz. Current-
phase\nrelationship in short superconducting weak leans. Physical Review L
etters\,\n25(16):1096\, 1970.\n\n[7] L. Aslamazov\,A. Larkin\, Yu N Ovchin
nikov\, and Z Fiz. Josephson effect in\nsuperconductors separated by a nor
mal metal. Sov. Phys. JETP\, 28(1):171\,\n1969.\n\n[8] I.O. Kulik. Macrosc
opic quantization and the proximity effect in sns junctions. Soviet Journa
l of Experimental and Theoretical Physics\, 30:944\, 1969.\n\n[9] J. Barde
en and J.L. Johnson. Josephson current flow in pure\nsuperconducting-norma
l-superconducting junctions.Physical Review B\,5(1):72\, 1972.\n\n[10] V.
Ambegaokar and A. Baratoff. Tunneling between superconductors.\nPhysical R
eview Letters\, 10(11):486\, 1963.\n\n[11] F.K. Wilhelm\, A.D. Zaikin\, an
d G. Schön. Superconducting current\nin narrow proximity wires. Czechoslo
vak Journal of Physics\, 46(4):2395–2396\,\n1996.\n\n[12] P. Dubos\, H.
Courtois\, B. Pannetier\, F.K. Wilhelm\, A.D. Zaikin\, and G. Schön.\nJos
ephson critical current in a long mesoscopic sns junction. Physical Review
\nB\, 63(6):064502\, 2001.\n\n[13] A. Spuntarelli\, P. Pieri\, and G. Calv
anese Strinati. Solu-\ntion of the bogoliubov–de gennes equations at zer
o temperature throughout\nthe bcs–bec crossover: Josephson and related e
ffects. Physics Reports\, 488(4-\n5):111–167\, 2010.\n\n[14] G. Watanabe
\, F. Dalfovo\, L.P. Pitaevskii\, and S. Stringari.\nEffects of periodic p
otentials on the critical velocity of superfluid fermi gases\nin the bcs-b
ec crossover. Physical Review A\, 83(3):033621\, 2011.\n\n[15] C.S. Lim\,
J.D. Leslie\, H.J.T. Smith\, P. Vashishta\, and J.P. Carbotte. Temperature
variation of the dc josephson current in pb-pb tunnel junctions. Physical
Review B\, 2(6):1651\, 1970.\n\n[16] S. Simonucci and G.C. Strinati. Equa
tion for the superfluid gap obtained by\ncoarse graining the bogoliubov–
de gennes equations throughout the bcs-bec\ncrossover. Phys. Rev. B\, 89:0
54511\, Feb 2014.\n\n[17] S. Simonucci and G. Calvanese Strinati. Nonlocal
equation for the supercon-\nducting gap parameter. Phys. Rev. B\, 96:0545
02\, Aug 2017.\n\nhttps://indico.unina.it/event/24/contributions/296/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/296/
END:VEVENT
BEGIN:VEVENT
SUMMARY:S. Poletto - Engineering superconducting transmon qubits (part 1)
DTSTART;VALUE=DATE-TIME:20190919T133000Z
DTEND;VALUE=DATE-TIME:20190919T150000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-189@cern.ch
DESCRIPTION:In this series of lectures I will describe how superconducting
transmon\nqubits are engineered\, designed\, and fabricated.\n\nI start i
ntroducing the building blocks of superconducting quantum\nprocessors from
an engineering point of view\, with a focus on working\nparameters and de
sign considerations. I will emphasize similarities with\nstandard microwav
e engineer elements such as transmission lines\,\nresonators\, and capacit
ive or inductive couplings.\n\nI will provide a deep insight on how the wo
rking parameters of the quantum\nprocessor are linked to the performances
of the device and to the lifetime\nof the qubits.\n\nI will conclude with
an overview of the common fabrication techniques to\nproduce superconducti
ng quantum processors.\n\nAt the end of this series of lectures the audien
ce will be familiar with\nequations and tools used to engineer superconduc
ting transmon quantum\nprocessors. Moreover\, they will know how to balanc
e the tradeoff between\nperformances and coherence times imposed at the de
sign stage.\n\nhttps://indico.unina.it/event/24/contributions/189/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/189/
END:VEVENT
BEGIN:VEVENT
SUMMARY:I. Mastroserio - Experimental proof of Quantum Zeno-assisted Noise
Sensing
DTSTART;VALUE=DATE-TIME:20190918T164000Z
DTEND;VALUE=DATE-TIME:20190918T170000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-299@cern.ch
DESCRIPTION:The ideal quantum Zeno effect is a robust method to protect th
e coherent dynamics of a quantum system. In particular\, in the weak quant
um Zeno regime\, repeated quantum projective measurements can allow the se
nsing of semi-classical field fluctuations.\nIn this talk I will show our
proposal and demonstration\, both theoretical and experimental\, of a nove
l noise-sensing scheme enabled by the weak quantum Zeno regime. We experim
entally tested these theoretical results on a Bose-Einstein Condensate of
87Rb atoms realized on an atom chip\, by sensing ad hoc introduced noisy f
ields.\n\nhttps://indico.unina.it/event/24/contributions/299/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/299/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A. Acin - Device-independent quantum information processing
DTSTART;VALUE=DATE-TIME:20190920T140000Z
DTEND;VALUE=DATE-TIME:20190920T153000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-193@cern.ch
DESCRIPTION:Device-independent quantum information processing represents a
new framework for quantum information applications in which devices are s
een as black boxes processing classical information. In particular\, no as
sumptions are made on the inner working of these devices except their quan
tum functioning. The lecture introduces the main ideas and tools of the de
vice-independent scenario and argues why it is especially relevant for qua
ntum cryptography applications.\n\nhttps://indico.unina.it/event/24/contri
butions/193/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/193/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A. Di Pierro - Introduction to Quantum Programming (part 1)
DTSTART;VALUE=DATE-TIME:20190921T070000Z
DTEND;VALUE=DATE-TIME:20190921T083000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-195@cern.ch
DESCRIPTION:Quantum programming languages have been introduced\nabout twen
ty years ago mainly from a theoretical\nperspective. Nowadays\, several ef
forts have been devoted to\nthe construction of real quantum architectures
. We can\ntherefore map the theoretical findings into concrete\nprogrammin
g platforms.\nIn this lecture\, we will introduce the notions at the basis
of\nhigh-level quantum programming and show some examples\nof quantum pro
grams by using existing platforms.\n\nhttps://indico.unina.it/event/24/con
tributions/195/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/195/
END:VEVENT
BEGIN:VEVENT
SUMMARY:V. Parigi - Multimode quantum optics in Continuous Variables Quant
um Information technologies
DTSTART;VALUE=DATE-TIME:20190916T070000Z
DTEND;VALUE=DATE-TIME:20190916T083000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-175@cern.ch
DESCRIPTION:In the continuous variables (CV) approach\, universal computat
ion can be identified via a universal set of Hamiltonians\, able to genera
te any arbitrary evolution as a combination of finite-time Hamiltonian uni
taries\, including Gaussian and non-Gaussian interaction - which are not e
asy to realise in an optical implementation. Differently form the discrete
variables (DV) approach the two-modes entangling gate in the CV encoding
is a Gaussian gate which can be implemented by combination of squeezing an
d linear optics. This has as consequence that the CV approach is particula
rly suitable for the one-way model of quantum computing based on cluster s
tate. I will revise experimental generation of multimode quantum states fo
r CV protocols and in particular the one based on optical frequency combs
and parametric processes. The protocols\, along with mode selective and mu
ltimode homodyne measurements\, allow for the implementation of reconfigur
able entanglement connections between the involved. This can be exploited
for fabricating entanglement structures with regular geometry as cluster s
tates or graphs with more complex topology which can emulate quantum physi
cal systems in complex structures or quantum protocols in complex networks
. I will also revise non-Gaussian operations\, which are necessaries to re
ach a form of quantum advantage in this scenario\n\nhttps://indico.unina.i
t/event/24/contributions/175/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/175/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A. Di Pierro - Introduction to Quantum Programming (part 2)
DTSTART;VALUE=DATE-TIME:20190921T090000Z
DTEND;VALUE=DATE-TIME:20190921T103000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-196@cern.ch
DESCRIPTION:Quantum programming languages have been introduced\nabout twen
ty years ago mainly from a theoretical\nperspective. Nowadays\, several ef
forts have been devoted to\nthe construction of real quantum architectures
. We can\ntherefore map the theoretical findings into concrete\nprogrammin
g platforms.\nIn this lecture\, we will introduce the notions at the basis
of\nhigh-level quantum programming and show some examples\nof quantum pro
grams by using existing platforms.\n\nhttps://indico.unina.it/event/24/con
tributions/196/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/196/
END:VEVENT
BEGIN:VEVENT
SUMMARY:S. Pilati - Adiabatic quantum computing and simulated quantum anne
aling (part 2)
DTSTART;VALUE=DATE-TIME:20190917T070000Z
DTEND;VALUE=DATE-TIME:20190917T083000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-180@cern.ch
DESCRIPTION:I will introduce some elements of adiabatic quantum computing\
, with special focus on approaches that aim to solve hard combinatorial op
timization problems via quantum annealing. The main features of currently
commercialized quantum annealing devices will be described.\nI will provid
e some notions concerning quantum Monte Carlo algorithms and discuss how t
hese simulation techniques are being use as a benchmark for quantum anneal
ers and as a tool to inspect if and when a quantum quantum annealing devic
es might display a quantum speed-up compared to classical optimization met
hods.\n\nhttps://indico.unina.it/event/24/contributions/180/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/180/
END:VEVENT
BEGIN:VEVENT
SUMMARY:G.P.Pepe - Physics and Applications of Superconducting Nanowire Si
ngle-Photon Detectors
DTSTART;VALUE=DATE-TIME:20190916T160000Z
DTEND;VALUE=DATE-TIME:20190916T173000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-179@cern.ch
DESCRIPTION:Superconducting Nanowire Single-Photon Detectors (SNSPD) are v
ery interesting for their overall performances in terms of system quantum
detection efficiency\, high maximum counting speeds achieved at wavelength
s up to near-IR\, ultra low darkcounts and very short jitter times.In this
lesson we'll present the operation principle of SNSPDs\, the fabrication
processes and the various approaches followed for both optical coupling an
d electrinic read-out. The use of SNSPDs in some quantum applications will
be also presented and discussed.\n\nhttps://indico.unina.it/event/24/cont
ributions/179/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/179/
END:VEVENT
BEGIN:VEVENT
SUMMARY:M. Bellini - Generation\, manipulation\, and detection of continuo
us-variable quantum states of light (part 1)
DTSTART;VALUE=DATE-TIME:20190916T140000Z
DTEND;VALUE=DATE-TIME:20190916T153000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-177@cern.ch
DESCRIPTION:I will introduce the basic concepts and provide real experimen
tal examples of quantum state engineering and measurement\, with special e
mphasis to continuous-variable quantum optical states of light. The first
lecture will introduce fundamental ideas and describe the basic tools\, su
ch as parametric down-conversion processes and balanced homodyne detection
\, for the manipulation and complete characterization of a quantum light f
ield. The second lecture will be devoted to presenting some advanced appli
cations to a variety of nonclassical states of light\, with illustrations
of the most fundamental concepts of quantum mechanics at play in the labor
atory.\n\nhttps://indico.unina.it/event/24/contributions/177/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/177/
END:VEVENT
BEGIN:VEVENT
SUMMARY:M. Bellini - Generation\, manipulation\, and detection of continuo
us-variable quantum states of light (part 2)
DTSTART;VALUE=DATE-TIME:20190917T133000Z
DTEND;VALUE=DATE-TIME:20190917T150000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-181@cern.ch
DESCRIPTION:I will introduce the basic concepts and provide real experimen
tal examples of quantum state engineering and measurement\, with special e
mphasis to continuous-variable quantum optical states of light. The first
lecture will introduce fundamental ideas and describe the basic tools\, su
ch as parametric down-conversion processes and balanced homodyne detection
\, for the manipulation and complete characterization of a quantum light f
ield. The second lecture will be devoted to presenting some advanced appli
cations to a variety of nonclassical states of light\, with illustrations
of the most fundamental concepts of quantum mechanics at play in the labor
atory.\n\nhttps://indico.unina.it/event/24/contributions/181/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/181/
END:VEVENT
BEGIN:VEVENT
SUMMARY:F. Scazza - Ultracold atomic Fermi gases in the strongly correlate
d regime (part 1)
DTSTART;VALUE=DATE-TIME:20190918T090000Z
DTEND;VALUE=DATE-TIME:20190918T103000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-184@cern.ch
DESCRIPTION:Ultracold atomic gases provide a formidable platform for quant
um simulation of a variety of models initially introduced in condensed mat
ter physics or other areas. One of the most promising applications of quan
tum simulation is the study of strongly correlated Fermi gases\, for which
accurate theoretical predictions are challenging even with state-of-the-a
rt approaches. In this lecture\, I will first briefly review the foundatio
ns of atom-light interactions and explain how these are exploited to cool\
, trap and manipulate atoms. I will then introduce ultracold atomic Fermi
gases\, from the non-interacting case to the famous strongly correlated BE
C-BCS crossover. I will also describe some recent experiments\, highlighti
ng the unique and fascinating aspects of crossover superfluids. In the sec
ond part of the lecture\, I will present a general introduction to the Fer
mi-Hubbard model and outline its realization with ultracold fermions in op
tical lattices\, highlighting the foremost experimental achievements so fa
r. To conclude\, I will shortly discuss some novel approaches to quantum s
imulation of quantum magnetism and long-range interacting systems.\n\nhttp
s://indico.unina.it/event/24/contributions/184/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/184/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A. Shafiei Aporvari- Cavity optomechanics
DTSTART;VALUE=DATE-TIME:20190918T133000Z
DTEND;VALUE=DATE-TIME:20190918T135000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-291@cern.ch
DESCRIPTION:In this work we are going to study cavity optomechanical syste
ms where the coupling between electromagnetic radiation and mechanical mot
ion is considered. In this fast-growing field\, the interaction of radiati
on field with the vibrational motions of a mechanical oscillator has many
promising applications such as precision force sensing and evaluations of
quantum physics at macroscopic scales. The standard and simplest optomecha
nical setup is a Fabry-Perot cavity in which one of the two mirrors is a v
ibrating micromechanical object. In fact\, it has been the first experimen
tally studied cavity optomechanical system. It is also possible to place a
mechanical element inside the optical cavity such as a flexible membrane
which could be exploited for applications such as quantum detection of wea
k forces\, displacements\, masses\, and accelerations. In this research\,
our main aim is to perform a quantum theoretical analysis on the power-noi
se spectrum by considering the phase measurements in a cavity optomechanic
s setup involving a coherently driven membrane in the middle of the cavity
. In other words\, mechanical motion of the system is studied by monitorin
g the phase of the optical cavity output.\n\nhttps://indico.unina.it/event
/24/contributions/291/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/291/
END:VEVENT
BEGIN:VEVENT
SUMMARY:E. Faraji - Quantum state transfer in protein α-helices.
DTSTART;VALUE=DATE-TIME:20190918T141000Z
DTEND;VALUE=DATE-TIME:20190918T143000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-293@cern.ch
DESCRIPTION:The Davydov model describes energy transfer in the hydrogen-bo
nded spines that stabilize protein α-helices. Its Hamiltonian has three p
arts: Ĥ =Ĥ ex+Ĥ ph+Ĥ int\, where Ĥ ex is the exciton Hamiltonian
(describing the internal amide-I excitations of the peptide groups)\, Ĥ
ph is the phonon Hamiltonian (describing deformational oscillations of th
e lattice) and Ĥ int is the interaction Hamiltonian (describing the inte
raction of amide-I excitation with the motions of the lattice sites).\nThe
primary goal of the thesis project is to go beyond the energy transfer an
d study the full state transfer along the α-helix by considering the Hami
ltonian Ĥ as corresponding to a spin network.\nPreliminary investigatio
ns on the phase dynamics\, which only account for Ĥ ex\, show the possib
ility of perfect state transfer between distant qubit.\nWe suspect however
that the addition of Ĥ ph+Ĥ int can wash out the coherence\, and we a
re currently estimating the time scale of this effect.\nSubsequently\, we
will pursue the same goal by modifying the Davydov model. In particular\,
we plan to introduce physically motivated anharmonic terms in Ĥ ph and s
ite-dependent coupling constants in Ĥ int. These could lead to coherence
recovery and hence facilitate the quantum state transfer through the prot
ein α-helices.\n\nhttps://indico.unina.it/event/24/contributions/293/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/293/
END:VEVENT
BEGIN:VEVENT
SUMMARY:F. Conte - The tuning-on-demand paradigm of van der Waals heterost
ructures: from first-principles calculations to possible applications
DTSTART;VALUE=DATE-TIME:20190918T143000Z
DTEND;VALUE=DATE-TIME:20190918T145000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-294@cern.ch
DESCRIPTION:In the recent years van der Waals heterostructures (vdWHs) hav
e received great interest\, due to their physical properties and attractiv
e applications in nanoelectronics and optoelectronics. These systems have
an unprecedented number of degrees of freedom\, such as number of layers\,
stacking order\, interlayer distance\, twist angle and so on. Tuning them
significantly affects the electronic properties of the system\, leading t
o a new “tuning-on-demand paradigm”\, which highlights how vdWHs can b
e suitably used for the implementation of new electronic devices and quant
um technologies. In this talk this paradigm is applied to vdWHs based on t
ransition-metal dichalcogenides (TMDs). First principles calculations of t
he structural and electronic properties of these systems unveil the richne
ss and tunability of such properties\, providing a contribution to new ele
ctronic devices architectures and quantum emitter configurations for nanop
hotonics and quantum information applications.\n\nReferences\n- Felice Con
te\, Domenico Ninno\, and Giovanni Cantele\, Phys. Rev. B 99\, 155429 (201
9)\n- Felice Conte\, Domenico Ninno\, and Giovanni Cantele\, “Bands tuni
ng in transition metal dichalcogenide heterostructures: the interplay betw
een thickness and electric field” submitted\n\nhttps://indico.unina.it/e
vent/24/contributions/294/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/294/
END:VEVENT
BEGIN:VEVENT
SUMMARY:I. Vagniluca - Quantum key distribution: field trials and practica
l challenges
DTSTART;VALUE=DATE-TIME:20190918T145000Z
DTEND;VALUE=DATE-TIME:20190918T151000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-295@cern.ch
DESCRIPTION:Quantum key distribution (QKD\, or more generically\, quantum
cryptography) is today the sole technology able to guarantee unconditional
security in sensitive data exchange\, as QKD protocols are in principle e
ffective regardless of the computational power available to a potential ea
vesdropper. Although QKD devices are already adopted outside the laborator
ies\, this technology is still far from a large-scale deployment in existi
ng fiber networks and telecom infrastructures\, due to practical issues as
low secret-key rate achievable\, high costs and high requirements in term
s of low-noise fiber links. These practical challenges in experimental QKD
are the main topic of my talk. Indeed\, my PhD project is focused on QKD
in-field demonstrations\, with the aim of proving its compatibility with a
lready installed fiber links\, while also testing its robustness against c
lassical signals co-propagating through the same fiber. Specifically\, I w
ill address two QKD field-trials involving a metropolitan fiber channel in
Florence and a submarine fiber link between Sicily and Malta. In addition
\, I will show the results of my collaboration with Technical University o
f Denmark\, in which we set up a prototype for high-dimensional QKD\, with
the aim of increasing the secret-key rate achievable while maintaining a
cost-effective experimental apparatus.\n\nhttps://indico.unina.it/event/24
/contributions/295/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/295/
END:VEVENT
BEGIN:VEVENT
SUMMARY:M. D'Antuono - Quantum Technologies with 2D-oxides
DTSTART;VALUE=DATE-TIME:20190918T160000Z
DTEND;VALUE=DATE-TIME:20190918T162000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-297@cern.ch
DESCRIPTION:Spintronics and Quantum Electronics represent the new candidat
es for future high-performance computer and information processes. The use
of the electron spin\, rather than charge\, as information carrier\, can
for instance define the unit of quantum information: the quantum bit (qubi
t). Recent developments have shown that the exploitation of the Rashba Spi
n Orbit Coupling (SOC) in two-dimensional (2D) materials is an innovative
and attractive solution for the quantum computation. For example\, SOC is
used for a more efficient charge to spin conversion in spin-orbit torque d
evices.\nHere we propose two-dimensional oxide (2D-oxides) systems as inno
vative quantum devices 1. The idea is to combine Rashba spin-orbit couplin
g (SOC)\, 2D-magnetism\, superconductivity (SC) and high-mobility in the s
ame 2D electron gas (2DEG) that is formed at the interface between wide ba
ndgap insulators oxides. We have demonstrated that the superconducting 2DE
G created at the interface between LaAlO3 and SrTiO3 (LAO/STO) becomes spi
n polarized by introducing a few unit cells of delta doping EuTiO3 (ETO)\,
an antiferromagnetic (AF) insulator iso-structural to STO 2. Firstly\, we
have investigated the interplay between ferromagnetism and Rashba spin-or
bit interactions by studying the magnetoconductance curves of the 2DEG as
a function of the applied gate voltage and temperature 3. Recently we have
also found that the interface exhibits\, under visible light\, a persiste
nt photoconductivity and anomalous Hall effect. This feature is probably r
elated to the different nature of the photo-excited spin-polarized 4f carr
iers due to ETO.\nThe application of oxide 2DEGs to advanced electronics r
equires also the creation of suitably designed nanodevices. We have realiz
ed (LAO/STO) tunnel devices using Helium focused ion beam (He-FIB). Our pr
eliminary measurements show that these devices are fully tunable and could
have interesting tunnel I-V characteristics. Our results show that these
oxide nanodevices could have a significant and far-reaching impact for new
quantum spintronic development.\n\nhttps://indico.unina.it/event/24/contr
ibutions/297/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/297/
END:VEVENT
BEGIN:VEVENT
SUMMARY:M. Minutillo - Anomalous Josephson effect in S/SO/F/S heterostruct
ures
DTSTART;VALUE=DATE-TIME:20190918T162000Z
DTEND;VALUE=DATE-TIME:20190918T164000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-298@cern.ch
DESCRIPTION:Hybrid mesoscopic systems in which conventional superconductiv
ity\, spin-orbit interactions\, and magnetism come into play at the same t
ime\, have attracted a lot of interest in recent studies\, allowing for th
e possibility to carry\, manipulate and transform quantum information\, wh
ich is a great advantage to develop components for applications in quantum
technology.\nIn particular\, superconducting circuits with Josephson junc
tions are among the leading candidates for the realization of the fundamen
tal building blocks of a quantum computer.\nIn this context\, we present a
study concerning the anomalous Josephson effect [1]\, predicting a finite
pair current in the absence of phase difference between the superconducto
rs.\nWe focus to S/SO/F/S system in which spin-orbit coupled and ferromagn
etic layers alternate. We calculate the Josephson current carried by the s
ubgap Andreev levels calculated as a function of the phase difference φ b
etween the two superconductors\, using a scattering matrix formalism\, bas
ed of phenomenological scattering matrices. We show that the coexistence o
f spin-orbit interaction and Zeeman effect is sufficient to break spin rot
ation and time-reversal symmetry in spatially separated regions of the jun
ction\, allowing to observe an anomalous Josephson effect. We also show th
at in the presence of an anomalous phase shift\, a direction dependent cri
tical current can show up.\nFinally\, future perspectives of our work will
be discussed\, such as a semi-empirical microscopic description of the su
perconducting proximity effect\, where the transport properties of the sys
tem are studied using the recursive Green’s functions method on a two- d
imensional Bogoliubov De Gennes tight-binding Hamiltonian.\n\nReferences:\
n[1] M. Minutillo\, D. Giuliano\, P. Lucignano\, A. Tagliacozzo\, and G. C
ampagnano\, Phys. Rev. B 98\, 144510 (2018).\n\nhttps://indico.unina.it/ev
ent/24/contributions/298/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/298/
END:VEVENT
BEGIN:VEVENT
SUMMARY:D. Salvoni - Double dark counts rates in NbTiN SNSPD
DTSTART;VALUE=DATE-TIME:20190918T170000Z
DTEND;VALUE=DATE-TIME:20190918T172000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-300@cern.ch
DESCRIPTION:In this work we present a study on the dark counts rate in a N
bTiN\nSuperconducting Nanowire Single Photon Detectros (SNSPD). The strip
is 80nm wide\, hence\nwe are in the 2D regime. We measure the distribution
of the time intervals elapsed between two\nconsecutive dark pulses at 4\,
2K and we do not observe a simple Poisson distribution as expected\nbut a
combination of two Poisson-like processes\, occurring with two dierent rat
es. The two\nmeasured dark counts rate exhibit a dierent dependence on the
bias current: one process\ndominates at lower bias and the other bocomes
more prominent as the current increases. In\nthe scenario presented by Ejr
naes et al. [1]\, this result could conrm that\, in this temperature\nregi
me\, dark counts are generated mainly by multiple consecutive\nuctuation e
vents. The result\ncan also be a footprint of two dierent process occurrin
g in the nanostrip.\n\nReferences\n[1] Ejrnaes M\, Salvoni D\, Parlato L\,
Massarotti D\, Caruso R\, Tafuri F\, Yang X Y\, You L X\, Wang Z\, Pepe G
P and Cristiano R 2019 Scientific Reports 9 8053\n\nhttps://indico.unina.
it/event/24/contributions/300/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/300/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A. Miano - Symmetric rf SQUID – universal element for Scalable Q
uantum Information Processing
DTSTART;VALUE=DATE-TIME:20190919T153000Z
DTEND;VALUE=DATE-TIME:20190919T155000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-301@cern.ch
DESCRIPTION:Building scalable Quantum Information Processing systems requi
res the ability to perform addressing\, readout\, control\, addressing and
signal distribution for individual quantum elements using low-power cryog
enic devices co-located or integrated at the mK stage. We propose to acco
mplish this using a novel superconducting device - Symmetric rf-SQUID. Thi
s device has been successfully tested as the fundamental element of a Symm
etric Traveling Wave Parametric Amplifier (STWPA)\, giving improved perfor
mances with respect to the existing TWPAs. Thanks to its flexibility\, the
Symmetric rf-SQUID allowed us to independently tune both even and odd non
linear terms of the Josephson current-phase relation. Based on this behavi
or\, we perform analytical and numerical simulations showing the possibili
ty to operate the Symmetric rf-SQUID in many scenarios as rf up-down conve
rsion mixers\, tunable-unitary gain phase shifters and linear tunable indu
ctances with an inductance-value-independent weak nonlinearity. The obtain
ed results will be presented and discussed.\n\nhttps://indico.unina.it/eve
nt/24/contributions/301/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/301/
END:VEVENT
BEGIN:VEVENT
SUMMARY:H. Ahmad - Electrodynamics of Highly Spin-Polarized Tunnel Josephs
on Junctions
DTSTART;VALUE=DATE-TIME:20190919T155000Z
DTEND;VALUE=DATE-TIME:20190919T161000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-302@cern.ch
DESCRIPTION:The continuous development of superconducting electronics is e
ncouraging several studies on hybrid Josephson Junctions (JJs)\, such as S
FS heterostructures. The competition between the superconducting order par
ameter in the electrodes and the ferromagnetic order parameter in the barr
ier leads to unconventional properties like: second harmonics in the curre
nt-phase relation (CPR)\, a transition in the phase difference between the
electrodes from 0 to π and the formation of spin-triplet Cooper pairs cu
rrents\, exploitable in spintronic devices and switchable elements in quan
tum/classical circuits. However\, most of the applications of SFS JJs in r
eal superconducting circuits are limited by the high decoherence in these
devices due to quasiparticles poisoning. We propose here an electrodynamic
characterization of a new kind of ferromagnetic JJs in which the barrier
is an insulating ferromagnet (tunnel-ferromagnetic spin-filter JJs). Spin-
filter JJs show evidences of MQT and an incomplete 0-π transition that co
uld enhance the capabilities of SFS JJs also as active elements. In order
to meet specific circuit requirements it is necessary a full comprehension
of the dissipation processes and the knowledge of the scaling laws with t
he thickness of fundamental electrodynamics parameters\, like the resistan
ce due to the quasiparticles and the capacitance of the device. We show th
at the Tunnel Junction Microscopic (TJM) model leads to a reliable and sel
f-consistent estimation of these parameters\, and that our self-consistent
approach can be fully extended to other type of tunnel JJs.\n\nhttps://in
dico.unina.it/event/24/contributions/302/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/302/
END:VEVENT
BEGIN:VEVENT
SUMMARY:G. Passarelli - Quantum annealing with dissipation
DTSTART;VALUE=DATE-TIME:20190917T153000Z
DTEND;VALUE=DATE-TIME:20190917T155000Z
DTSTAMP;VALUE=DATE-TIME:20200929T222610Z
UID:indico-contribution-24-285@cern.ch
DESCRIPTION:Quantum annealing is a branch of quantum computation aimed at
solving optimization problems. The optimization problem is encoded in a qu
antum Hamiltonian\, whose ground state is the wanted solution. Standard qu
antum annealing works as follows. The qubit system is prepared in the grou
nd state of a simple Hamiltonian. Then\, the qubits are evolved in time us
ing a time-dependent Hamiltonian that\, at the final time\, coincides with
the one used to encode the optimization problem. If the evolution is slow
compared to the minimal level spacing\, then the adiabatic theorem of qua
ntum mechanics ensures macroscopic occupation of the target ground state a
t the end of the evolution.\n\nThe algorithm is limited by small spectral
gaps\, occurring in the presence of quantum phase transitions\, and is rea
lized in the presence of dissipation\, due to the interaction with the env
ironment. While disruptive in general\, low-temperature environments can s
ometimes favor quantum annealing\, improving the success probability. This
beneficial effect can be further enhanced using pauses at specific times
during the dynamics\, favoring thermal relaxation towards the ground state
.\n\nMy talk will present some results concerning quantum annealing in the
presence of dissipation\, with and without pauses\, for the p-spin model\
, a prototypical Ising system often used as a benchmark for quantum anneal
ing. This model is hardly studied experimentally due to its full connectiv
ity and the presence of p-body interactions. However\, its rotational symm
etry allows for an easy numerical analysis in the weak coupling limit. I w
ill show that dissipation and pauses can improve the success probability o
f the quantum annealing of this model.\n\nhttps://indico.unina.it/event/24
/contributions/285/
LOCATION:
URL:https://indico.unina.it/event/24/contributions/285/
END:VEVENT
END:VCALENDAR