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### Title & Abstract

9/5 15:40-16:40 Session 1Dr. Ying-Chen Chen

Title:Building a Programmable Quantum Processor with Cold Atoms

Abstract:

In this lecture, I will introduce how to use trapped single-atom arrays to build a programmable quantum processor for the study of quantum computing and simulation. Starting from an overview of quantum computing and simulation with this platform, I will then describe the crucial and detailed steps towards building such a processor, including sub-K laser cooling of atoms, generation of two-dimensional arbitrary optical tweezer arrays, efficient loading of atoms to 2D tweezer arrays, atom rearrangement, quantum simulation of spin model, single-qubit gates with Raman transition, two-qubit gates with Rydberg transition and interactions, and large-scale quantum gate operations. I will also discuss the possible applications of using such a platform to solve quantum approximate optimization problem.

Prof. Tzu-Ling Chen

Title: Adventures with Macro- and Micro-Optical Cavities: The Challenges and How they help to Explore the World of Atoms and Molecules

Abstract:

Laser spectroscopy is a powerful means of revealing the fine structures of atoms and molecules, which help us to explore science and increase real-world applications. To uncover the physical or chemical properties with higher resolution or at the single particle level, an optical cavity is a straightforward way to amplify the light-matter interaction in a compact size by directly increasing the interaction path. In pursuing higher cavity enhancements, however, some technical limitations, such as light-cavity coupling efficiency and laser sources, have restricted the signal-to-noise ratio for revealing the detail when cavity-enhanced spectroscopy is applied to objectives with dynamical features or owning multiple species. In this talk, I will describe our efforts to push cavity-enhanced spectrometers to surpass these limits.

In the first part, I will describe the use of a chip-scale optical frequency comb as a broadband excitation laser source for spectroscopy of real-time gas sensing. In the second part, I will describe how we use cavity ring-down time measurements for detecting moving single-particle aerosol. In the final part, I will describe my adventure in chiral microcavities. Because of the reciprocal properties of molecular chirality, achieving chiral control in a cavity has been a challenge. By taking the advantage of the newly developed non-reciprocal chiral organic thin film, the chirality can be preserved upon reflection from a mirror. I will show the evidence of the amplification of the chiral properties in a planar microcavity.

9/6 11:00-12:00 Session 3

Prof. Hung-Wen Chen

Title: Ultrashort Pulse Laser Machining: From Laser-Material Interaction to Laser Machining Applications (via Deep Learning)

Abstract:

The talk will be mainly divided into two parts. 1. The mechanism of laser-material interaction in laser ablation. 2. Various laser machining applications including some of those using deep learning techniques.

9/6 12:30-12:50 Young Scientist Session (20mins)

Dr. Kuldeep Suthar

Title: Many-body localization

Abstract:

The phenomenon of many-body localization (MBL) is attracting significant theoretical and experimental interest over the past few years. The signatures of MBL have been observed in recent cold-atom experiments in optical lattices. First, I shall discuss a brief overview on this novel state of matter. And, then I will show our recent investigations on synthetic and non-Hermitian many-body localization. Our studies pave a way to observe several interesting features of MBL which can be realized with recent cold-atom experiments with artificial gauge field and non-Hermiticity.

9/6 12:50-13:10 Young Scientist Session (20mins)

Nadia Daniela Rivera Torres

Title: Probing topological protected transport in finite-sized Su-Schrieffer-Heeger chains

Abstract:

The need to storage and process big quantities of information, as well as to be able to explain troublesome quantum many-body problems, that not even today’s most powerful supercomputers can solve, has awakened a huge interest in quantum computation during the last decades. The development of quantum computers is based on one of the fundamental principles of quantum mechanics, the superposition principle. The whole formalism is developed in terms of qubits, which are the coupling of two isolated quantum states. Any two level quantum-mechanical system can be used as a qubit. Many fields in physics have proposed physical implementations of qubits. For instance, in the field of topological systems, insulators and superconductors have been widely used in quantum computation. Their experimental simulations are feasible in the field of ultracold matter, what makes them very convenient as quantum simulators, since they have a high degree of controllability. A particular example of a quantum simulator in this field, is the Su-Schrieffer-Heeger model (SSH model), which was originally proposed to explain the electrons’ behaviour in polymers, more specifically in polyacetylene chains, but it has become widely known as the simplest system in which topological phase transitions may occur. This simple model describes polarized fermions hopping on a one-dimensional staggered lattice, composed by two sublattices and N unit cells, where each unit cell hots two sites, each of them belonging to a different sublattice. The intracell v and intercell w hopping amplitudes, are responsible for the dynamics of the system. The model presents two characteristic topological phases, the trivial and the non-trivial one. In the non-trivial phase, the chain hosts two zero-energy edge modes, which are topologically protected states localized at the the edges of the lattice. These edge modes are of great interest because their robustness makes them a good candidate for quantum computation. When implementing experimentally the SSH model, instead of infinite chains, only some dimers can be fabricated. It is the common belief that in finite SSH chains, the wavefunctions of the edge modes stay strongly localized at the edges of the chain, and decay exponentially in the bulk, with a penetration depth depending on the ratio of the hopping amplitudes (w/v), such that the transport of topologically protected information between them would not be possible. However, in this study we show that a transport length Lc, which is way larger than the penetration depth, i.e., \xi << Lc, exists for finite size SSH chains, such that, as long as the lattice size is smaller than this transport length, the transport of information with topological protection between the two supported edge states is possible.

9/6 13:10-13:30 Young Scientist Session (20mins)

Santiago Figueroa Manrique

Title: Localization, edge states and topology in the two-body SSH model

Abstract:

In this work, we study the localization, edge states and topology of the two-body SSH model. First, we introduce the single-particle SSH model to illustrate some important concepts, such as edge states and localization. Next, we define our topological invariant, the Zak phase, and discuss its quantization under inversion symmetry. Moreover, we extend the Zak phase to interacting systems with cotranslational symmetry which may be non-Hermitian and biorthogonal. Furthermore, a way to numerically compute this invariant through the Wilson-loop approach is provided. Finally, we examine the two-body SSH model by the means of a canonical transformation to map the internal degrees of freedom into pseudo-spin ones, together with the center-of-mass and relative coordinates approximation, to calculate the Zak phase numerically. In the end, we find, utilizing the IPR, the edge states in both dimerizations D1 and D2 and compute them with direct diagonalization; we obtain that these come as a result of the interplay between the geometry, the boundaries, the freely moving particles and the interactions. On the other hand, the Zak phase is used to characterize the topological structure of the discrete bands, yielding non-trivial topology as the values of π and 0 depend not only on the ratio ω/ν but also on the interaction strength.

9/6 13:30-13:45 Young Scientist Session (15mins)

朱俐安

Title: Fabrication and Measurement of Quantum Noise Squeezing from Monolithic LiNbO3 Waveguide Chips

Abstract:

The purpose of this report is to study the generation of quantum squeezed light sources on an integrated photonic chip which was developed to miniaturize and scale up photonic circuits. The use of a single-pass optical parametric amplifier (OPA) is an attractive way to obtain non-classical light source-squeezed states, giving one of the quadrature terms a chance to reach a smaller uncertainty than the standard quantum limit (SQL) under the premise of the uncertainty principle.

In this study, an OPA and a wavelength splitter were successfully integrated on a single chip based on the Titanium-diffused Lithium Niobate waveguide. The OPA employed periodically poling to achieve quasi-phase-matching and pumped with a 775 nm CW light to generate 1550 nm squeezed light. An adiabatic coupler (AC) is introduced on the chip after OPA to separate the 1550 nm squeezed light and 775 nm pump light into two waveguide channels. Finally, we used a balanced homodyne detector to detect the squeezed light and examine the squeezing level on the RF spectrum analyzer.

9/6 13:45-14:00 Young Scientist Session (15mins)

呂浩宇

Title: Study on refractive index of micro-rings toward squeeze generation

Abstract:

Start from the theory of squeezed state, and discuss what is the solution on chip scale. We would focus on the general phenomenon as four-wave mixing with chi_3 effect in material. Thus, a micro-ring would be applied as a resonator ,and we would share the simulations how we started from.

Prof. Ray-Kuang Lee

Title: Machine-Learning Enhanced Quantum State Tomography

Abstract:

This lecture will cover the fundamental details about machine-learning (ML) enhanced quantum state tomography (QST) for squeezed states from scratch. Implementation of machine learning architecture with a convolutional neural network will be illustrated and demonstrated through the experimentally measured data generated from squeezed vacuum states. Recent progress in applying such a ML- QST as a crucial diagnostic toolbox for applications with squeezed states will also be covered, from quantum information process, quantum metrology, and macroscopic quantum state generation.

9/7 11:00-12:00 Session 5 (60mins)

Prof. Yi-Shan Lee

Title: Single photon generation and detection physics and technology

Abstract:

Single-photon generation and detection is at the forefront of modern optical physics. This lecture is intended to provide a comprehensive overview of single-photon science and technology for those launching experimental research in single- and correlated-photon-based science.

9/7 13:30-14:30 Session 6 (60mins)

Prof. Paul-Antoine Moreau

Title: Low light imaging & Imaging with quantum states of light

Abstract:

When the intensity of the light illuminating a scene is made very dim, several sources of noise can become an issue and prevent imaging of that scene to be performed.

Such noises can be technical, such as sensor noise or spurious light dazzling the sensor but can also be of a fundamental nature.

Light being composed of photons the intensity of a whole image cannot be indefinitely fractioned. When imaging at low light levels localized single photon detection will noisily represent the whole image. This can be described as a noise called “shot-noise”.

Throughout the presentation we will see ways to mitigates some of these noises.

We will particularly put emphasis on how we can use single photon sensitive cameras to witness some quantum aspects nature of light in images, and how in turn we can use specific quantum properties of light (quantum correlations between two photons) to improve noise in imaging.

9/7 15:00-15:20 Young Scientist Session (20mins)

Dr. 莊又霖

Title: Optical-density enhanced quantum entanglement via four-wave mixing process

Abstract:

A strong continuous-variable quantum entangled state of light can be generated in four-wave mixing process with a four-level atomic system. By properly choosing the parameters of the light-atom interaction system, the optimized entanglement can be achieved up to -14 dB at an optical density of approximately 1,000, which has been realized in atomic media. With the optimum condition found in the parameter spaces, the degree of optimum entanglement and the optical gain of output fields can be enhanced by the increment of optical density. The strong entanglement as well as large optical gain provides promising applications in quantum communications.

9/7 15:20-15:40 Young Scientist Session (20mins)

Dr. 謝憲毅

Title: Wigner current in decoherence

Abstract:

In this work, we experimentally studied the quantum dynamics in squeezers. With the help of machine learning-enhanced quantum state tomography, a full monitor of experimental Wigner flow (phase space flux) as well as the degradation information can be accomplished. The observed quantum dynamics are illustrated for the stagnation point and non-trivial topological order in squeezers, as well as the identification of decoherence current due to the interactions with the environment. Our experimental demonstration provides a novel paradigm to measure the quantumness and non-classicality through the flux of quantum information in the phase space.

9/7 15:40-16:00 Young Scientist Session (20mins)

Dr. 張恩瑞

Title: Measurement-free Quantum Error Correction of Grid States

Abstract:

We introduce the measurement-free quantum error correction scheme for Gottesman-Kitaev-Preskill (GKP) grid states.

An additive Gaussian error can be auto-corrected while the number of GKP states required is exponentially suppressed.

9/7 16:00-16:15 Young Scientist Session (15mins)

陳映如

Title: Quantum Random Number Generator Using Vacuum Fluctuation

Abstract:

The importance of generating true random numbers rises in the application such as cryptography as the computing power improved tremendously due to the development of quantum computers. The intrinsic indeterministic property of quantum mechanics makes quantum processes great methods to generate true random numbers. Among all the quantum processes, optical processes can yield a higher random number generation rate, especially in the continuous variable scheme. The purpose of this work is to implement a high-speed random number generator using vacuum fluctuation to generate quality random number, and ultimately extend to using squeezed state to boost up the generation rate.

Prof. Wen-Te Liao

Title: Introduction to x-ray quantum optics

Abstract:

Since the discovery of Mössbauer effect, the resonant nuclear scattering of synchrotron x rays has became useful tool for investigating fundamental physics, e.g., gravitational effect, and material science, e.g., condensed matter physics. The commission of x-ray free electron laser even shed new light on coherent control of nuclear quantum state. In this lecture, we will briefly introduce the recent progress on x-ray quantum optics.

9/8 11:00-12:00 Session 8 (60mins)

Prof. Watson Kuo

Title: Non-trivial photonic band topology in tailored regular lattice of microwave resonators

Abstract:

Strongly coupled resonators present collective modes allowing the guiding of electromagnetic waves. Because of the tunability in coupling strength by the orientation configuration, split-ring resonators(SRRs) provide an ideal system for manipulating the inter-resonator coupling on demand. By tailoring the orientation texture of a lattice of SRRs, one can simulate interesting non-interacting hopping models. As an example, we present the topologically non-trivial band structures of one-dimensional Su–Schrieffer–Heeger model and Aubry-André-Harper model. We also discuss the transport property via edge modes, such as transport range and velocity.