Title:
Variational quantum algorithms

Abstract:
Variational quantum algorithms (VQAs) constitute a class of hybrid quantum-classical algorithms that are envisioned to be appropriate for noisy intermediate scale quantum processors. The majority of VQAs focus on quantum simulation, and particularly finding properties of many-body quantum systems, such as the ground state energies of complicated molecules. Other problems, such as optimization and machine learning are also being explored with this approach. In VQAs, the quantum processor is where the quantum state is variationally prepared and where measurements are made, while the classical computer performs optimization. After reviewing the concept of VQAs and their main aspects: state preparation, measurement, and optimization, I will highlight our work on designing efficient, compact ansatze both for many-body and for optimization problems.

BIO:
Sophia Economou is a Professor of Physics and the Hassinger Senior Fellow of Physics at Virginia Tech. She focuses on theoretical research in quantum information science, including quantum computing, quantum communications, and quantum simulation algorithms.

Title:
Quantum networks, computation, and simulations with spins in diamond

Abstract:
Optically active defects in solids are a promising system for quantum science and technology. By connecting together small quantum processors of multiple spins through optical links a quantum network can be formed. Such a network is naturally extendable to large sizes by adding independent modules and provides a powerful platform for quantum computation, simulation and communication.

Here I will discuss our progress on realising such quantum networks based on spin in diamond. I will introduce the control of such spins as qubits [1] and the optical links to entangle them over long distances [2]. In particular, I will discuss how small quantum processors can be formed for quantum computation and simulation [3,4,5].

[1] C. E. Bradley et al., Phys. Rev. X. 9, 031045 (2019)[2] B. Hensen et al., Nature 526, 682 (2015)[3] M. H. Abobeih et al., Nature 576, 411 (2019)[4] M. H. Abobeih et al., arXiv:2108.01646 (2021)[5] J. Randall et al., arXiv:2107.00736 (2021)

BIO:
Tim Taminiau is a PI at QuTech at the Delft University of Technology. His group (established in 2015) uses solid-state defect spins to investigate the fundamentals of quantum information and the physics of coupled spin systems. He graduated from the University of Twente in 2005 and obtained a PhD at the Institut de Ciències Fotòniques (ICFO) in Barcelona. Before returning to the Netherlands as a Marie Curie fellow in 2011, Tim investigated optically active defects at the California Institute of Technology and Brown University. Tim was awarded an ERC starting grant and the Dutch Veni and Vidi career grants. In 2015, he was awarded the Fresnel prize for fundamental contributions to quantum optics and electronics.

Title:
Verification of Quantum Computation

Abstract:
Quantum computers promise to efficiently solve not only problems believed to be intractable for classical computers but also problems for which verifying the solution is also considered intractable. This raises the question of how one can check whether quantum computers are indeed producing correct results. This task, known as quantum verification, has been highlighted as a significant challenge on the road to scalable quantum computing technology. We review the most significant approaches to quantum verification and compare them in terms of structure, complexity and required resources. We also comment on the use of cryptographic techniques, which, for many of the presented protocols, has proven extremely useful in performing verification. Finally, we discuss issues related to fault tolerance, experimental implementations and the outlook for future protocols.

References:

Verification of quantum computation: An overview of existing approaches
A Gheorghiu, T Kapourniotis, E Kashefi
Theory of computing systems 63 (4), 715-808

Quantum certification and benchmarking
J Eisert, D Hangleiter, N Walk, I Roth, D Markham, R Parekh, U Chabaud, …
Nature Reviews Physics 2 (7), 382-390

Verifying quantum computations at scale: A cryptographic leash on
quantum devices
Thomas Vidick
Bulletin of the American Mathematical Society 57(1):1

BIO:
Elham Kashefi is Professor of Quantum Computing at the School of Informatics, University of Edinburgh, and Directeur de recherche au CNRS at LIP6 Sorbonne Universite. She co-founded the fields of quantum cloud computing and quantum computing verification, and has pioneered a trans-disciplinary interaction of hybrid quantum-classical solutions from theoretical investigation all the way to actual experimental and industrial commercialisation (Co-Founder of VeriQloud Ltd). She has been awarded several UK, EU and US grants and fellowships for her works in developing applications for quantum computing and communication. She is the senior science team leader of the quantum computing and simulation hub in the UK and member of the executive team of the EU quantum internet alliance.

Title:
Hexagonal Boron Nitride – emerging platform for Quantum Photonics

Abstract:
Engineering robust solid-state quantum systems is amongst the most pressing challenges to realize scalable quantum photonic circuitry. While several 3D systems (such as diamond or silicon carbide) have been thoroughly studied, solid state emitters in two dimensional (2D) materials are still in their infancy.
In this presentation I will discuss the appeal of an emerging van der Waals crystal – hexagonal boron nitride (hBN). This unique system possesses a large bandgap of ~ 6 eV and can host single defects that can act as ultra-bright quantum light sources. In addition, some of these defects exhibit spin dependent fluorescence that can be initialised and coherently manipulated. On top of that, the hBN crystals can be carefully sculpted into nanoscale photonic resonators to confine and guide light at the nanoscale. It hence has all the vital constituents to become the leading platform for integrated quantum photonics. To this extent, I will highlight the challenges and opportunities in engineering hBN devices and will frame it more broadly in the growing interest with 2D materials nanophotonics.

BIO:
Professor Igor Aharonovich received his PhD in 2010 from the University of Melbourne and spent two years in Harvard as a postdoctoral researcher in the group of Prof Evelyn Hu. In 2013 Igor returned to Australia and joined the University of Technology Sydney (UTS) where is currently a full Professor and the UTS node director of the ARC Centre of Excellence for Transformative Meta-Optical Systems.
Igor’s group is focusing on exploring single emitters in wide band gap semiconductors, such as diamond and more recently hexagonal boron nitride. His group is also interested in innovative approaches for nanofabrication of nanophotonics devices for quantum circuitry. But most importantly – Igor’s group has members from 11 different countries which forms a vibrant and a dynamic environment.
Igor received numerous international awards and recognitions including the 2017 Pawsey medal from the Australian Academy of Science, 2019 CN Yang Award – honors young researchers with prominent research achievements in physics in the Asia Pacific region and the 2020 Kavli foundation early career lectureship in materials science. He was also elected as a fellow of the Optical Society (class 2021).

Title:
Quantum-limited measurements: One physicist’s crooked path from relativity theory to quantum optics to quantum information

Abstract:
Quantum information science has changed our view of quantum mechanics. Originally viewed as a nag, whose uncertainty principles restrict what we can do, quantum mechanics is now seen as a liberator, allowing us to do things, such as secure key distribution and efficient computations, that could not be done in the realistic world of classical physics. Yet there is one area, that of quantum limits on high precision measurements, where the two faces of quantum mechanics remain locked in battle. I will trace the history of quantum-limited measurements, from the use of nonclassical light to improve the phase sensitivity of an interferometer, to the modern perspective on the role of entanglement in improving measurement precision.

BIO:
Carlton M. Caves is a theoretical physicist who has worked mainly on quantum metrology, the science of how to make the most sensitive measurements in the presence of the inherent uncertainties introduced by quantum mechanics. Caves was an undergraduate at Rice University, from which he received a BA in Physics and Mathematics in 1972. He received the PhD in Physics from the California Institute of Technology in 1979 and continued at Caltech as a Research Fellow and then Senior Research Fellow till 1987. From 1988 till 1992 he was Associate Professor of Electrical Engineering and Physics at the University of Southern California. He moved to the University of New Mexico as Professor of Physics and Astronomy in 1992, was recognized as a Distinguished Professor in 2006, and was Director of UNM’s Center for Quantum Information and Control from its founding in 2009 till his retirement from teaching and administration in 2018. Now Distinguished Professor Emeritus and Research Professor of Physics and Astronomy at UNM, Caves is a Fellow of the American Physical Society and the American Association for the Advancement of Science and is a member of the US National Academy of Sciences.

Research Interests: Carlton Caves began his research career as a relativity theorist, became a quantum optician to explore the noise in gravitational-wave detectors, and morphed to a quantum information scientist, interested in how to persuade quantum systems to do jobs we want, instead of doing what comes naturally. He is perhaps best known for having proposed to improve the sensitivity of interferometric gravitational-wave detectors by injecting squeezed-vacuum light into the normally unused (antisymmetric) input port of an interferometer, an early example, before anyone thought about it this way, of replacing what comes naturally, the vacuum entering the unused port, with the squeezed vacuum that improves sensitivity. Caves continues research today on projects drawn from quantum information theory, quantum optics, and quantum metrology. Focus on particular research projects, important, indeed crucial though they are, diverts attention from the ultimate point. The overarching goal, too ambitious and therefore fatally attractive, is to explore what it is that makes the world quantum, to understand why the world turns out to be that way, and to formulate a coherent and consistent way to think about the quantum world.

Title:
Quantum circuits, and the future of quantum technology in the cloud

Abstract:
Since 2016 when the first quantum processor was launched in the cloud by IBM for public use, open-source quantum computing software platforms have been proliferating. As we transition our focus from building a quantum processor to building a full-stack quantum system with emphasis on expanding computational capability, the role of quantum software developers becomes more prominent than before. With this vision, we launched Qiskit in 2017 an open-source quantum software development kit, to invite software developers to the quantum computing community. In this talk, I present the current status of quantum computing hardware technology and how quantum software developers can help to advance quantum computing. Starting with basics of quantum computing and IBM’s quantum hardware roadmap, I will go over how to program with quantum circuits, the basic computational routine that maps the quantum algorithms to execute in the quantum hardware. At the end of the talk, I will discuss the future directions for the quantum software where we exploit both quantum and classical resources together to maximize the quantum volume, quantum processing speed, and variety of quantum computing.

BIO:
Dr. Jay Gambetta is an IBM Fellow and the Vice President of IBM Quantum, in charge of IBM’s overall Quantum initiative.

He was named as an IBM Fellow in 2018 for his scientific work on superconducting qubits, quantum validation techniques, implementation of quantum codes, improved gates and coherence, and near-term applications of quantum computing—in addition to establishing IBM’s quantum strategy.

Under his leadership, the IBM Quantum team has made a series of major breakthroughs in the quantum industry: starting with launching the IBM Quantum Experience – the world-first cloud-based quantum computing platform for users to access real quantum computers, the IBM Quantum team released Qiskit – an open source software development kit for developing quantum programs, and deployed the IBM Quantum System One, a family of quantum processors for clients that now includes the 27 qubit Falcon and 65 qubit Hummingbird quantum processors. IBM Quantum continues to expand in the market by providing 42 quantum systems opened for service over the cloud from anywhere in the world, building the foundations of the quantum industry with a community of partners advancing quantum science and applications.

Dr. Gambetta received his Ph.D. in Physics from Griffith University in Australia. In 2014, he was named as a Fellow of the American Physical Society and has over 130 publications in the field of quantum information science with over 23000 citations.

Title:
Polarization textures and sub-picosecond thermalization of Bose-Einstein condensates in plasmonic lattices

Abstract:
Bose-Einstein condensation (BEC) has been realized for various particles or quasi-particles, such as atoms, molecules, photons, magnons and semiconductor exciton polaritons. We have experimentally realized a new type of condensate: a BEC of hybrids of surface plasmons and light in a nanoparticle array. The condensate forms at room temperature and shows ultrafast dynamics. We have achieved such Bose-Einstein condensation also at the strong coupling regime, and shown by varying the lattice size that the thermalization in these systems is a simulated process that occurs in 100 femtosecond scale [2]. This new platform is ideal for studies of differences and connections between BEC and lasing.

Recently, we have determined the spatial and temporal first order correlations of the strongly coupled BEC, and observed non-exponential decay distinguishing the phenomenon from lasing and nonordered states. We have observed that the condensate phase has a non-trivial phase structure which in turn leads to complex polarization patterns.

We determine the phase of the BEC by a phase retrieval algorithm, for the first time for any type of condensate. The non-trivial phase is likely due to non-linearities related to the strong coupling nature of the condensate. We have shown that also nanoparticle arrays made of dielectric materials can be brought to the strong coupling regime. This opens new possibilities for lasing and BEC studies due to reduced losses and different single particle optical response.

Title:
Quantum algorithms

Abstract:
While the power of quantum computers remains far from well understood, many quantum algorithms have been developed that provide various degrees of improvement over classical computation. This talk will present an overview of some of the major quantum algorithms and quantum algorithmic techniques. Topics to be covered include quantum analogs of Markov processes, simulations of Hamiltonian dynamics, and quantum algorithms for high-dimensional linear algebra.

Title:
Harnessing Nitrogen Vacancy Centers in Diamond for Next-Generation Quantum Science and Technology

Abstract:
Advanced quantum systems are integral to both scientific research and modern technology enabling a wide range of emerging applications. Nitrogen vacancy (NV) centers, optically-active atomic defects in diamond, are directly relevant in this context due to their single-spin sensitivity and functionality over a broad temperature range. Many of these advantages derive from their quantum-mechanical nature of NV centers that are endowed by excellent quantum coherence, controllable entanglement, and high fidelity of operations, enabling opportunities to outperform their classical counterpart. In this talk, I will present our recent efforts in developing NV-based quantum sensing platform and technologies. Specifically, we demonstrated electrical control of the coherent spin rotation rate of a single-spin qubit in an NV-spintronic hybrid quantum system. By utilizing electrically generated spin currents, we are able to achieve efficient tuning of magnetic damping and the amplitude of the dipolar fields generated by a micrometer-sized resonant magnet, enabling electrical control of the Rabi oscillation frequency of NV spin qubits. In addition, exploiting a state-of-the-art NV quantum sensing platform, we achieved optical detection of magnons with a broad range of wavevectors in magnetic insulator thin films. Our results highlight the potential of NV centers in designing functional hybrid solid-state systems for next-generation quantum-information technologies. The demonstrated coupling between NV centers and magnons further points to the possibility to establish macroscale entanglement between distant spin qubits and paves the way for developing transformative NV-based quantum computer.

Title:
Exciton-Polaritons in microcavities with embedded atomically thin crystals

Abstract:
Monolayer transition metal dichalcogenides (TMDC) have emerged as a new platform for studies of tightly bound excitons and many-body excitations in ultimately thin materials. Their giant dipole coupling to optical fields makes them very appealing for implementing novel photonic devices, and for fundamental investigations in the framework of cavity quantum electrodynamics [1].
Our recent experiments show that the regime of strong light-matter coupling between excitons in atomically thin transition metal dichalcogenides and microcavity photons can be accessed while retaining the canonical valley-properties of the TMDC layer [2] and that the effect of bosonic condensation of exciton-polaritons (see Figs. 1a,b), driven by excitons in an atomically thin layer of MoSe2, has become within reach [3]. We address the pending question on the emergence of long-range first-order spatial coherence, via interferometric g(1)(t) measures (Fig. 1c). I will finally discuss the emergence of coherence in polaritonic resonances at room temperature and their implementation in fully tuneable optical lattices with integrated WS2 monolayers as a first step towards exploring correlations in highly non-linear synthetic lattices [4].

[1] C. Schneider et al. Nature Commun. 9, 2695 (2018).[2] N. Lundt et al. Nature nanotechnology 14.8 770-775. (2019).[3] C. Anton-Solanas, et al. Arxiv 2009.11885 (2020).[4] L. Lackner et al. Arxiv 2102.09565 (2021).

Title:
The magic of moiré quantum matter

Abstract:
The understanding of strongly correlated quantum matter has challenged physicists for decades. The discovery three years ago of correlated phases and superconductivity in magic-angle twisted bilayer graphene led to the emergence of a new materials platform to investigate strongly correlated physics, namely moiré quantum matter. These systems exhibit a plethora of quantum phases, such as correlated insulators, superconductivity, magnetism, Chern insulators, and more. In this talk I will review some of the recent advances in the field, focusing on the newest generation of moiré quantum systems, where correlated physics, superconductivity, and other fascinating phases can be studied with unprecedented tunability. I will end the talk with an outlook of some exciting directions in this emerging field.

Graduated from École Polytechnique and Doctor in Quantum Physics from Université Paris 6, Pascale Senellart joined the CNRS in 2001. She was appointed senior researcher in 2011 and has been professor of quantum mechanics at Polytechnique since 2014.

Her research activity is at the interface between nanosciences, semiconductor physics and quantum optics. Her team developed quantum light sources of unprecedented efficiency and this work was recognised by the CNRS Silver Medal in 2014 and the election as a Fellow of the Optical Society of America (OSA) in 2018.

In addition to her research activity, P. Senellart is co-founder of Quandela, a company that sells unique photon sources and is in charge of promoting industrial transfer within the DIM SIRTEQ dedicated to quantum technology in the Île-de-France region