Now at #PQC, Nicolas Didier from @rigetti on full stack quantum computing with superconducting qubits
#PQC #LTQI @rigetti Nicolas Didier gives papers usin Rigetti QCS with VQE to compute ground states of H₂, LiH, NaH and a few other chemistry computations.
You can als solve linear problems by variational quantum lienar eigensolvers, tuning A to optimize A|x⟩=|b⟩
#LTQI #PQC

Now at #IWQNS, Kavan Modi from @MonashUni on Stochastic proceses and application to quantum networks
#LTQI @MonashUni Kavan Modi: Classical stochastic processes can ofte be modelled by MArkov Chains, ore hidden markov chains, where the last n responses (n:= Markov order) are lumped together. #LTQI #IWQNS

Now at #IWQNS Zhang Zheshen form @UoA on Entanglement-Assisted Quantum Photonic Sensor Networks
#LTQI @uoa Zhang Zheshen uses enatgled light to detect targets. His entaglement source, low brightness limit: # photon/mode N_s ≫ 1. Phase correlation |⟨â_s â_I⟩|≈√N_S ≫ N_S. #LTQI #IWQNS

Now at #IWQNS, Kanupriya Sinha from @ArmyResearchLab and @JQInews on Tailoring fluctuation phenomena in nanophotonic systems: collective effects in Casimir-Polder forces & non-Markovian dynamics in atomic collective states
#LTQI @ArmyResearchLab @JQInews Kanupriya Sinha; Casimir–Polder forces are important for integrated atom systems.
The interaction of a dipole at distance z of a mirror is U ∼ – ℏΓ₀/16(k₀z)³ : At z∼10 nm, U∼10 mK.
Where k₀ ← ω₀ (2 level split)
#LTQI #IWQNS

Now, at IWQNS, Sara Mouradian from @Berkeley_ions on Engineering Quantum Networks
#LTQI IWQNS @Berkeley_ions Sara Mouradian did her PhD on NV centers, and now works on ion traps.
A single photon detected from two NV⁻ centers allows to prepare them in entangled state. Her NV's are at 10K. Current rate of entanglement is limite to much less than spin coherence time
#LTQI #IWQNS

Now at #IWQNS, Ashlesha Patil, Saikat’s student at @UoA speaks on Classical Simulation of Stabilizer Circuits
#LTQI #IWQNS @uoa Ashlesha Patil demonstrates her Matlab tool, based on Gotoesman and Aaronson algorithm. For an arbitrary stabilizer state. If not a graph, proposes local unitaries converting it to a graph states, impements them (or others), and draw the relevant graph state
#LTQI #IWQS

Now at #IWQNS, Saikat Guha from @UoA on photonic quantum computing with discrete variable cluster states
#LTQI @uoa Saikat Guha’s approach is on the “where is my photon ?” approach, based on progressive fusion of clusters. But
we do not understand the fundamental limits of corresponding measurement.
#LTQI #IWQNS

Now at #IWQNS, Rafael N. Alexander from @UNM on quantum computing with continuous variable clusters
#LTQI @UNM Rafael N. Alexander: Once you have a graph states allows you to do quantum computing with local operations, through measurement based quantum computation (MBQC). ∃ a sort of dictionnary translating circuits into graphical operations.
#IWQNS #LTQI

Now ar #IWQNS Lincoln D. Carr @coschoolofmines on quantifying complexity in quantum phase transitions via mutual information complex networks
#LTQI @coschoolofmines Lincoln D. Carr: In present quantum device (@dwavesys and analog devices) can already be described by networks difficult to simulate. Networks can be in the Hamiltonian, or arise spontaneously in the state. Here is about these spontaneous networks
#LTQI #IWQNS

Now at #IWQNS, @vparigi81 from @lkb_lab on Engineering non-Gaussian entangled complex photonic graph states .
#LTQI @vparigi81 @lkb_lab Recent #LTQI threads from me on simlar talks by @vparigi81 :

https://twitter.com/fgrosshans/status/1098964327548272640

,and

https://twitter.com/fgrosshans/status/996325413273120770

(includes link to a video)

Now at #IWQNS @SumeetKatri6
from @LSU on Robust NEtwork Architectures and topologies for entanglement distibution #LTQI #IWQNS @LSU Sorry, wrong twitter handle: it’s @SumeetKhatri6
#LTQI #IWQNS

Now at #IWQNS, Don Towsley from @UMassAmherst on Entanglement routing and switching in quantum networks #LTQI @UMassAmherst Don Towsley looks at repeaters/routers/switchs
With m links/link
Phase 1: link entanglement succeeds with p=1 – (1 — p₀)^m
Phase 2: splicing the links succeeds with probability q
#LTQI #IWQNS

Now at #IWQNS, Prithwish Basu from U. Massachusetts on Routing and Scheduling in cClassiacal Networks #LTQI Prithwish Bashu: Modern networks are not like internet in the 1970s. They’re no longer nice graphs, but now some king of hypergraphs with a mishmash of technologies.
#IWQNS #LTQI

Now at #IWQNS, Roberta Zambrini, from @IFISC_mallorca on Quantum complex networks: introduction, Synchronization ans Noiseless subspaces #LTQI @IFISC_mallorca Roberta Zambrini: classical complex networks are used to study the phenomenon of spontaneous synchronization. It has been recently generalized into the quantum regime
#LTQI #IWQNS

Now at #IWQNS, Patrick Thiran from @EPFL presents an overview of classical an and complex networks. Mainly on classical networks, and on tools who might be applied to quantum networks.
#LTQI @EPFL Patrick Thiran: Networks are complex. Layer abstraction helps to “divide and conquer”, but this abstraction comes at a cost, and sometimes it not worth it.
#LTQI #IWQNS

Now at #QICA, Damian Markham from @ScienceSorbonne presents an Introduction to Quantum Networks
#LTQI @ScienceSorbonne Damian Markham’s talk is actually steamed here facebook.com/watchparty/624…

Seated for a talk by Mio Murao, form @UTokyo_News_en on Higher order quantum operations of blackbox unitaries and causal structure of the blackboxes. #LTQI @UTokyo_News_en Mio Murao ([村尾 美緒) uses quantum computer to understand physics. What we can do do and what we cannot do are physics problems.
#LTQI

Seated for a seminar on “Quantum Information Technology for Network”, by Qin Hai, from CAS Quantum Network Co., ltd, in Shanghai. This talk will essentially be focused on Chinese progress
#LTQI Qin Hao: The chinese quantum satellite Micius has 3 mission. 1/ Act as a trusted quantum node, with QKD rate of 1 kbps (recently 400 kbps) ; 2/ Distribute entanglement between 1200km distant locations; 3/ Groud to satellite quantum state teloprtation
#LTQI

Seated for a talk by Mathieu Bozzio, on "Towards trusting your local Franprix's payment terminal..." a.k.a. “Money money money, must be funny, in a quantum world !”.

Joint work with Eleni Diamanti and myself, arXiv:1812.09256 arxiv.org/abs/1812.09256
#LTQI Mathieu Bozzio: in the 1970s, Stephen Wiesner invented a quantum banknotes scheme, with security based on the no-cloning theorem.
Mint→Client→Bank

For quantum credit cards, there is classical communication between the Merchant and Bank:
Mint→Client→Merchant→Bank
#LTQI

Now seated for a seminar by Antoine Grospellier, from @inria_paris, on Constant overhead quantum fault-tolerance with quantum expander codes.

Associated paper: arXiv:1808.03821 arxiv.org/abs/1808.03821
#LTQI @inria_paris Antoine Gropellier recalls the principle of quantum fault tolerance with concateneated Steane codes. Without correction, with error probability p, a circuit C, |C| gates and m qubits, Pr(wrong output)≤p|C|,
With code, 7m qubits, ≤c₀|C| gates, Pr(wrong)≤cp²|C|
#LTQI

Seated for a seminar by Francesco Arzani on his work with Nicolas Treps and Giulia Ferrini on
Polynomial approximation of non-Gaussian unitaries by counting one photon at a time (arXiv:/1703.06693 arxiv.org/abs/1703.06693 / PRA 95 052352 dx.doi.org/10.1103/PhysRe… )
#LTQI Francesco Arzani: It’s difficult to define computation in a continuous variable (CV) set-up. People usually chose specific encoding of qubits. But Francesco (and myself!) finds encoding independent definitions more interesting.
#LTQI