Now at #JapanEUWorkshop, Shuntaro Takeda on A strategy for large-scale optical quantum computing #LTQI

Shuntaro Takeda: use a deterministic approach, a loop to increase scalability. Determinism is brought by continuous variable (CV) system, which need 5 gates to be universal: 3 linear, squeezing and cubic gate (the hard one) #LTQI #JapanEUWorkshop

Shuntaro Takeda: both discrete CNOT and CV cubit gates need χ⁽³⁾ and are therefore difficult, but the latter is at least deterministic.

#LTQI #JapanEUWorkshop

#LTQI #JapanEUWorkshop

Now at #JapanEUWorkshop , Anthony Laing on Photonic simulations of molecular quantum dynamics #LTQI

Anthony Laing essentially looks a photnic simulation of vibrational modes of molecules

Anthony Lang looks at selective dissociation with a single quantum of vibration NH₃→NH₂+H. These molecular transition can be manipulated through control of the wavepacket. #LTQI

Now Erika Kawakami on Capacitive read-out of the Rydberg states towards the realization of a quantum computer

using electrons on helium

#LTQI #JapanEUWorkshop

using electrons on helium

#LTQI #JapanEUWorkshop

Erika Kawakami: Why use electrons on helium? The system is clean: electrons float in vacuum, far prom nuclear spin and other charges. Electron qubits are 1µm away, which will be useful for surface codes #LTQI #JapanEUWorkshop

Erika Kawakami: The spin-state is used a qubit state, the rydberg states are auxiliary states. T₂=100 s for spin states. 1 qubit gates through ESR; 2-qubit gate using Coulomb interacton #LTQI #JapanEUWorkshop

Now, Eleni Diamanti on Practical Secure Quantum Communications #JapanEUWorkshop #LTQI

Eleni Diamanti: The current solution to secure network links: Symmetric + Asymmetric cryptography. Recent development to fight the threat of quantum computers: postquantum cryptography. Quantum cryptography offers the advantage to be future proof #LTQI

Eleni Diamanti: REal security will have to combine the the use of classical and quantum cryptography. nature.com/articles/nphys…

#LTQI #JapanEUWorkshop

#LTQI #JapanEUWorkshop

Now, Yoshiro Takahashi from @KyotoU_News on Advanced quantum simulator with novel

spin and orbital degrees of freedom #LTQI

spin and orbital degrees of freedom #LTQI

@KyotoU_News Yoshihiro Takahashi: With ¹⁷³Yb nuclear spins, we have a SU(6) Fermi-Hubbard model. They observe formation of SU(6) Mott insulator.

#LTQI #JapanEUWorkshop

#LTQI #JapanEUWorkshop

@KyotoU_News Yoshihiro Takahashi ’s next traget: SU(6) quantum magnetism. A difficulty is measuring spin correlation, which is achieved through singlet-triplet oscillation compined with photo association #LTQI #JapanEUWorkshop

Now, Christian Groß, on quantum simulation of the Hubbard model, from hidden correlations to magnetic polarons. #LTQI

Christian Groß simulates Hubbard model with cold atoms in optical lattices. Li atoms hop with amplitude t. Currently, they only have global control, no local control. #LTQI

Christian Groß observes the atoms with quantum gas microscopy. He observes a single plane desctructively through a high NA objective every 30s. #LTQI

Now, Carlo Reita on “Towards scalable silicon quantum computing” #LTQI

Carlo Reita‘s work is on quantum dots in Si. The initial state is easy to set using electrostatic gates. The manipulation and the readout are also done with elcetrostatic gates #LTQI

As a CMOS person, Carlo Reita is not scared by 100 millions of objects, all the same. We just need to find how to make a few of them. #LTQI

Now, Yoshihis Yamamoto on Physica of Quantum-toClassical Crossover and coherent Ising machines #LTQI

Yoshihisa Yamamoto : The goal is to build acelerators for combinatorial an continuous optimization problems. A traditonal quantum computer essentially uses a Grover algorithm and gets a quadratic improvement, but scaling essentailly remains exponential. #LTQI

Yoshihisa Yamamoto: One needs to use hueristic quantum machines, like a quantum neural network. He compares it to quantum annealers in arxiv:1805.05217 arxiv.org/abs/1805.05217 #LTQI

Now, Philippe Grangier, from @InstitutOptique on Recent progress on continuous variable quantum cryptography #LTQI

@InstitutOptique Sadly, I’m on low battery, so I don’t know how long I’ll be able to livetweet Philippe Grangier’s talk #LTQI

@InstitutOptique Philippe Grangier:«We have very good proofs for that, many of them don by @letonyo»

Now, Nobuyuki Imoto from @osaka_univ_e on Frequency conversion of single photons emitted from atom/ion quantum memory for telecommunications #LTQI

@osaka_univ_e Noboyuki Imoto’s focus is on a global quantum network. It is useful for long haul QKD, the goal is to go beyond the *relayed* quantum network of journals.aps.org/prl/abstract/1… #LTQI

@osaka_univ_e Nobuyuki Imoto works on quantum repeaters in a fibre network. He limits the decoherence via decoherence free subspaces (DFS). #LTQI

@IQSTpress Jörg Wrachtrup: Spins can be used to measure chemical parameters, temperature, mechanical forces (through deformation of hosting Crystal), electric or magnetic fields. #LTQI

Jörg Wrachtrup: the magnetic field sensitivity is 10⁻⁸ T/√Hz (single nuclear spin, 10 nm away).

It can be used for single protein spectrosopy. (Shi et al. Science 347 science.sciencemag.org/content/347/62… ) #LTQI

#LTQI

It can be used for single protein spectrosopy. (Shi et al. Science 347 science.sciencemag.org/content/347/62… ) #LTQI

#LTQI

Now, Masahiro Kitagawa (Osaka University) on Room temperature nuclear hyperpolarization and quantum encoding for hyper-sensitive NMR and MRI

#LTQI

#LTQI

Masahiro Kitagawa: NMR/MRI sensitivity can be increased by a factor ×1000 by combining 3 quantum techniques:

1. Initialization:

Dynamic Nuclear Polarization (DNP) using photoexcited triplet electron.

1. Initialization:

Dynamic Nuclear Polarization (DNP) using photoexcited triplet electron.

Masahiro Kitagawa: Triplet electron spins are excited with a laser, the electron couple to nuclear spin and then decay. One can then restart the cycle.

One can engineer the different relaxation pathways by deuterating the pentacene molecules #LTQI

One can engineer the different relaxation pathways by deuterating the pentacene molecules #LTQI

Now, Frak Wlhelm-MAuch from @Saar_Uni on Quantum Computers in 2018.

Now Yasunobu Nakamura from on the “Macroscopic quantum machines” ERATO project jst.go.jp/erato/nakamura…

#LTQI

#LTQI

YAsunobu Nakamura will focus on Integrated quantum circuits because of time constraints.

He investigates information quantum thermodynamics in the quantum domain, at a small scale. Fault-tolerant quantum computers look a lot like perpetual quantum machines.

#LTQI

He investigates information quantum thermodynamics in the quantum domain, at a small scale. Fault-tolerant quantum computers look a lot like perpetual quantum machines.

#LTQI

Yasunobu Nakamura: a superconducting qubit is a nonlinear resonator. The non-equidistant energy levels allow to use the two lowest levels as a qubit

#LTQI

#LTQI

Seated for a seminar by Aephraim Steinberg grom @UofT : How to count one photon and get a result of 1000 – and other experiments on quantum measurement

#LTQI

#LTQI

Now seated for a seminar by Zizhu Wang (王子竹) on

Entanglement and Nonlocality in Infinite 1D Systems (joint work with Sukhwinder Singh, and Miguel Navascués)

arXiv:1608.03485 arxiv.org/abs/1608.03485 / Phys. Rev. Lett. 118, 230401 (2017)

doi.org/10.1103/PhysRe…

Entanglement and Nonlocality in Infinite 1D Systems (joint work with Sukhwinder Singh, and Miguel Navascués)

arXiv:1608.03485 arxiv.org/abs/1608.03485 / Phys. Rev. Lett. 118, 230401 (2017)

doi.org/10.1103/PhysRe…

Zizhu Wang looks at symmetrisation techniques to move between condense-matter n-body systems with no symmetry and infinite translation invariant systems. This procedure works when one only has access to local information

#LTQI

#LTQI

Zizhu Wang now look at the classical marginal problem: Does a finite distribution P(A₁, A₂, …, A_n) come from a translation invariant distribution ? Yes iff P_{A₁…A_{n-1}}(a₁,…,a_{n-1}) = P_{A₂…A_{n}}(a₁,…,a_{n-1})

#LTQI

#LTQI

Nows at #MCQS, Rafał Demkowicz-Dobrzański from (@UniWarsawski ) on the grand unified theory of quantum metrology.

#LTQI

#LTQI

Now at #MCQS, Cristina Butucea from @ENSAEParisTech on Local Asymptotc Equivalence of Quantum Gaussian Model

#LTQI

#LTQI

@ENSAEParisTech Cristina Butucea defines an experiment (Ω, A, P) : a measurable space together with a family of probability distributions. Together with Markov Kernels, it allows to define Le Cam‘s distance

#LTQI #MCQS

#LTQI #MCQS

@ENSAEParisTech Cristinea Butucea: Two sequences P₁,n , P₂,n are asymptotically equivalent if their distance →0, which implies thatn many asymptotic risk bound for tests, estimators etc. carry over from a model to the other

#LTQI #MCQS

#LTQI #MCQS

Now at #MCQS, Andrea Rocchetto, from @UCL @UniofOxford on «Machine learning in quantum information theory, a selection of results» #LTQI

@ucl @UniofOxford Andrea Rocchetto defines the PAC (porbabilistically aproximate correct) models, and defines the concept of PAC-learnable: a concept is PAC-learnable iff one can guess a good model for arbitrary input distributions

#LTQI #MCQS

#LTQI #MCQS

@ucl @UniofOxford Andrea Rocchetto: PAC learning on quantum states. The goal is to guess σ havig the same probability ditribution under a binary POVM than the training set ρ. Aaronson proved in 2007 that the problem is really different from tomography. #LTQI #MCQS

Now at #MCQS, Valentina Parigi from @lkb_lab on Reconfigurable optical implementation of quantum complex networks

#LTQI

#LTQI

@lkb_lab .@vparigi81’s synchonously pumped OPO (SPOPO) leads to a complex multimode entanglement structure. She then uses multimode homodyne detection to characterize the corresponding 16-mode covariance matrix.

Eigenmodes found from diagonalization are Hermite-Gauss modes

#LTQI #MCQS

Eigenmodes found from diagonalization are Hermite-Gauss modes

#LTQI #MCQS

@lkb_lab @vparigi81 .@vparigi: showed that all 151k+ partitions of 10 frequency modes are not separable: we are indeed in a multipartite entanglement case.

#LTQI #MCQS

#LTQI #MCQS

Now Chiara Machiavello from@unipv on “Witnessing quantum capcities of noisy communication channels”

#LTQI #MCQS

#LTQI #MCQS

Now at #MCQS, @GerardoAdesso from @UniofNottingham on ""Towards superresolution surface metrology: Quantum estimation of of angular & axial separations"

#LTQI #MCQS

#LTQI #MCQS

@GerardoAdesso @UniofNottingham .@GerardoAdesso teh curs of Raygleigh criterion for high resolution imaging: “two point sources can be resolved by direct imaging if their separation is at least of the order of the width of their point spread function in the image plane”

#LTQI #MCQS

#LTQI #MCQS

@GerardoAdesso @UniofNottingham .@GerardoAdesso : But is this the ultimate limit? We need quantum estimation theory, and the quantum Cramér-Rao bound for that. #LTQI #MCQS

Seated (late) for Andrew Jordan’s (from @UofR) talk at #MCQS on “Estimating with continuous quantum measurement” #LTQI

And now, some physics with Young-Sik Ra from @lkb_lab on “Experiment for generating Non-Gaussian quantum states of multimode light field”

#LTQI

#LTQI

@lkb_lab Young-Sik Ra creates multimode squeezed vacua by pumping an OPO with a multimode pump (a frequency comb with ∼10⁵ modes)

#LTQI

#LTQI

Young-Sik Ra‘s key operation ins single photon subtraction : â|n⟩=√n|n–1⟩.

The conventional implementation, based on a beamsplitter and ingle photn detection heralding only works for single mode states.

#LTQI

The conventional implementation, based on a beamsplitter and ingle photn detection heralding only works for single mode states.

#LTQI