Subradiant States of a 1D Qubit Chain

Subradiant States of a 1D Qubit Chain
Subradiant States of a 1D Qubit Chain [mehr]

Certification of Quantum Measurements and New Entangled Quantum Probes

Certification of Quantum Measurements and New Entangled Quantum Probes
In the quantum information literature, self-testing refers to the action of uniquely determining a quantum state based solely on the statistics of measurement outcomes and minimal assumptions. These quantum self-testing protocols are more stringent than well-known Bell tests. While violation of a Bell inequality for a bipartite system establishes that its quantum state is entangled, it cannot certify, for instance, that its quantum state is maximally entangled. We extend self-testing techniques to certification of quantum measurements in various physical settings. [mehr]

Part 1: Scattering theory in quantum opticsPart 2: Scaling up and understanding the limits of photonic inverse design

Part 1: Scattering theory in quantum optics Part 2: Scaling up and understanding the limits of photonic inverse design
Part 1: Quantum optical systems can often be modelled as a low-dimensional quantum system (such atwo-level system, Jaynes-Cummings system etc.) coupling to an electromagnetic bath. [mehr]

Fundamental science by high-power microwaves - Millimeter-wave spectroscopy of positronium hyperfine structure and further ( Prof. Dr. Akira Miyazaki)

Fundamental science by high-power microwaves - Millimeter-wave spectroscopy of positronium hyperfine structure and further
The microwave technology has been one of the important tools in fundamental physics since Rabi's pioneering work on hydrogen atoms. In this seminar, direct spectroscopy of positronium hyperfine structure with very high frequency microwaves, often referred to as millimeter or sub-THz waves, will be discussed. [mehr]

Direct laser cooling to Bose-Einstein condensation (Alban Urvory)

Direct laser cooling to Bose-Einstein condensation
Laser cooling methods are virtually ubiquitous for the production of ultracold quantum gases. Yet in order to reach quantum degeneracy, a complementary step of lossy and inefficient evaporative cooling has so far been required (with few specific exceptions). [mehr]

Nuclear-driven Electronic Coherences in Polyatomic Molecules

Nuclear-driven Electronic Coherences in Polyatomic Molecules
Electronic coherences in molecules has emerged as a ‘grand challenge’ in molecular sciences due to the role that electronic correlations and dynamics play in structure and bonding. In the field of attosecond science, electronic coherences can be prepared by attosecond pulses, producing purely electronic wavepackets which persist while the atoms are ‘frozen’ (i.e. a few femtoseconds). Once the atoms unavoidably start to move, the wavepacket could dephase and the electronic coherence would be lost. However, some suggested that nuclear motion could modify or even induce electronic coherences. [mehr]

Large deviations and cMPS in open quantum dynamics

Large deviations and cMPS in open quantum dynamics
In this talk I will describe a perspective on the dynamics of Markovian open quantum systems based on the study of the statistical properties of ensembles of quantum trajectories. This "thermodynamics of quantum trajectories" approach is to dynamics what the standard equilibrium configuration ensemble method is for statics. [mehr]

Strong-field dynamics of molecules: electron-nuclear correlation (Prof. Jian Wu)

Strong-field dynamics of molecules: electron-nuclear correlation
The primary phase of the light-molecule interaction is the photon energy absorption and deposition. Although the electron is much lighter than the nuclei, there is a strong electron-nuclear correlation for molecules exposed to strong laser fields. The photon energy deposits into the nuclei governs the succeeding dynamics and thus the fate of the molecules. [mehr]

New quantum SI units and fundamental constants (Dr. Savely Karshenboim)

New quantum SI units and fundamental constants
The International system of units, SI, has just been changed once again. The new definitions, which concern the kilogram, ampere, kelvin, and mole, are to come in force on May, 20. Similarly to the definition of the metre in terms of the speed of light, those four units are now defined in the terms of exact adopted values of fundamental constants, such as the elementary charge, Planck, Boltzmann, and Avogadro constants. [mehr]

Theodore Maiman Series: Physics and applications of epsilon-near-zero materials (Prof. Dr. Robert Boyd)

Physics and applications of epsilon-near-zero materials
In this talk, we describe some of the unusual optical properties of materials, known as epsilon-near-zero (ENZ) materials, for which the dielectric permittivity is very small. We describe some of the unusual geometrical optical properties of such materials and present theoretical predictions of how fundamental radiative properties are modified under such conditions. We also describe some of the nonlinear optical properties of these materials. Recent work has shown that optical materials can display an extremely large optical nonlinear response in their ENZ spectral region. [mehr]

Spatial entanglement patterns and Einstein-Podolsky-Rosen steering in a Bose-Einstein condensate (Dr. Matteo Fadel)

Spatial entanglement patterns and Einstein-Podolsky-Rosen steering in a Bose-Einstein condensate
Atomic Bose-Einstein condensates (BECs) are highly controllable isolated quantum systems with long coherence times, and offer applications in metrology and quantum information processing. We experimentally prepare two-component Rubidium-87 BECs, consisting of a few hundred atoms, on an atom-chip. Using state-selective potentials to tune the collisional interactions (one-axis twisting dynamics), we prepare many-particle non-classical states. After a time-of-flight expansion, high-resolution images allows us to access sub-regions of the atomic density distribution of various shapes and measure the spin correlations between them. [mehr]
This talk is devoted to modern methods of laser spectroscopy, with the special focus on applications that require extreme ultraviolet (XUV) radiation and extreme resolution. [mehr]

Integrated quantum memories in diamond and silicon photonics (Dr. Ralf Riedinger)

Integrated quantum memories in diamond and silicon photonics
Linking remote quantum systems promises a host of new applications, ranging from distributed quantum computing to entanglement enhanced telescopes. Long distance quantum networks will require many nodes consisting of interfaces between local quantum memories and optical photons. While there are many contenders for these quantum nodes, nanophotonic implementations are particularly attractive: Once a single system works, it can be reproduced many times at minimal marginal costs. [mehr]

Single-shot interpretations of von Neumann entropy (Henrik Wilming)

Single-shot interpretations of von Neumann entropy
In quanum information theory, the von Neumann entropy usually arises in i.i.d settings, while single-shot settings are commonly characterized by (smoothed) Renyi entropies. I discuss new results that give single-shot interpretations to the von Neumann entropy under appropriate conditions. [mehr]

IMPRS-APS: Light matter interaction at the level of one and no atom (Prof. Dr. Leuchs)

IMPRS-APS: Light matter interaction at the level of one and no atom
In this talk, the exotic story of light matter interaction at the evel of one and even no atom is discussed. A single atom in free space can have significant effects on a single light beam producing e.g. sizeable phase shifts. Regarding the dynamics, a future goal is demonstrating time reversibility of spontaneous emission. But also without any atom, when studying empty space, there are intriguing concepts and future opportunities. [mehr]

Dissipative engineering of cold atomic systems (Dr. Jorge Yago)

Dissipative engineering of cold atomic systems
Cold atom systems in optical lattices provide a promising platform for a wide variety of applications, ranging from quantum simulation to quantum metrology, due to their extremely high tunability and the ability to derive microscopic models under well-controlled approximations that give access to accurate descriptions. The proper characterization of those systems requires, in many scenarios, taking into account that they are subject to some dissipation sources, as dissipation can drastically modify the behaviour of the known phases of matter or even generate new ones. However, the description of open systems can quickly become numerically unaffordable. [mehr]

Experimental tests of quantum non-locality beyond EPR-steering and beyond Bell (Prof. Howard Wiseman)

Experimental tests of quantum non-locality beyond EPR-steering and beyond Bell
In this talk I will present an unpublished theory and experiment for two quantum nonlocality scenarios which generalise EPR-steering and Bell, respectively. in the sense of having weaker assumptions and thus more stringent experimental conditions. The first is to allow a finite amount of FTL communication of classical information in an EPR-steering scenario. The second relates to the recent theorem of Bruckner using "Wigner friends" in place of the determinism assumption in some formulations of Bell's theorem. [mehr]

Kick-off WORKSHOP: Quantum Emitters in Non-Conventional Baths (European Research Council)

Quantum Emitters in Non-Conventional Baths (European Research Council)

An effective description of Ramsey tunnel-coupled 1D Bose gases with the Pokrovsky-Talapov model (Valentin Kasper)

An effective description of Ramsey tunnel-coupled 1D Bose gases with the Pokrovsky-Talapov model
The high flexibility of ultracold atoms allows for the design, control and thorough investigation of quantum matter. In this work we consider two one-dimensional Ramsey tunnel-coupled Bose gases and elaborate on its relation to the Prokrovsky-Talapov model. Further, we study the ground state with variational wave-functions and explore the experimental relevant finite system size effects. Finally, we discuss possible quench protocols in order to study the non-equilibrium evolution of the Pokrovsky-Talapov model and predict experimental relevant quantities such as the phase and the density. [mehr]

Flat Optics: a new approach to structured light, polarization control and lenses (Prof. Federico Capasso)

Flat Optics: a new approach to structured light, polarization control and lenses
Metasurfaces enable arbitrary control of the wavefront of light by locally manipulating polarization in addition to amplitude and phase. As a result, multiple optical functions can be encoded with greatly reduced complexity that be accessed by changing the input polarization, wavelength and k-vector. Unique ways to generate structured light, a new polarization optics that greatly surpasses the capabilities of the standard and a new class of lenses that correct aberrations without requiring multiple stacked lenses have emerged from this approach. [mehr]

SDP relaxations for the certification of properties of many-body quantum states (Flavio Baccari)

SDP relaxations for the certification of properties of many-body quantum states
Understanding the properties of many-body systems is one of the crucial questions for the development of quantum technologies. An ubiquitous problem is to certify that a given many-body quantum system satisfies an operational property: is this given system in an entangled state? Does it contain the solution to a classical optimisation problem? [mehr]
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The 2nd Law: History and Fiction (Prof. Assa Auerbach)

The 2nd Law: History and Fiction
The talk The 2nd Law: History and Fiction discusses the history of Maxwell’s Demon, the Second Law of Thermodynamics, and its connection to Information Theory. It shows how these concepts can be explained to non-physicists in a comic book of an adventure story called “Max the Demon vs Entropy of Doom’’. [mehr]

Entanglement in non-unitary critical spin chains (Romain Couvreur)

Entanglement in non-unitary critical spin chains
Entanglement entropy has proven invaluable to our understanding of quantum criticality. It is natural to try to extend the concept to “nonunitary quantum mechanics”, which has seen growing interest from areas as diverse as open quantum systems, noninteracting electronic disordered systems, or nonunitary conformal field theory (CFT). [mehr]

IMPRS-APS: Realizing Feynman’s Dream of a Quantum Simulator (Prof. Immanuel Bloch)

Realizing Feynman’s Dream of a Quantum Simulator
More than 30 years ago, Richard Feynman outlined his vision of a quantum simulator for carrying out complex calculations on physical problems. Today, his dream is a reality in laboratories around the world. [mehr]

Quantum physics with compound atom-ion systems (Dr. Antonio Negretti)

Quantum physics with compound atom-ion systems
In this talk I shall illustrate how ultracold quantum systems of atoms and ions can be used for quantum simulation and information processing as well as for investigating many-body quantum physics. I shall thus present a few theoretical examples on how to control an atomic bosonic Josephson junction with a single trapped ion, the formation of molecular ions, and how to engineer long-ranged atom-ion interactions with laser fields and Rydberg excitations. [mehr]

A source of light-matter entanglement for quantum state distribution over hybrid matter platforms (Dr. Pau Farrera)

A source of light-matter entanglement for quantum state distribution over hybrid matter platforms
In this talk I will speak about our source of light-matter quantum states based on laser-cooled atoms. In particular, I will explain the capabilities developed in order to transfer photonic qubits from this system to another matter platform that consists on a crystal doped with rare-earth ions. Photonic qubits generated by the atomic cloud were frequency converted and temporally shaped in order to have an optimum interaction with the ions in the crystal. These capabilities enabled to perform quantum state transfer between these two very different matter systems: the laser-cooled gas and the crystal. [mehr]

Entanglement Renormalization for Weakly Interacting Fields (Ali Mollabashi)

Entanglement Renormalization for Weakly Interacting Fields
I will introduce a specific method how to generalize cMERA in presence of interactions. The method is based on Hamiltonian renormalization of spatial degrees of freedom. Using this method I will work out a circuit starting from an appropriate IR state and ending up with the vacuum state of phi^4 theory. [mehr]

IMPRS-APS Talk: Ultrafast electron control: from the particle accelerator on a chip to attosecond charge transfer in a Schottky junction (Prof. Dr. Hommelhoff)

Ultrafast electron control: from the particle accelerator on a chip to attosecond charge transfer in a Schottky junction
Firstly, I will deal with a new way of accelerating charged particles based on femtosecond laser pulses and nanophotonic structures. The concept is exactly the same as in classical RF and microwave accelerators, only with roughly five orders of magnitude faster oscillating driving fields and structures that are smaller by the same factor. With the help of such small lithographically produced dielectric structures we have demonstrated not only efficient acceleration of electrons, but also deflection and focusing. Currently, we are building a prototype "accelerator on a chip". The current status will be reported. [mehr]

Arrival time distributions and spin in quantum mechanics-A Bohmian perspective (Siddhant Das)

Arrival time distributions and spin in quantum mechanics-A Bohmian perspective (Siddhant Das)
The arrival time statistics of spin-1/2 particles governed by Pauli's equation, and defined by their Bohmian trajectories, show unexpected and very well articulated features. Comparison with other proposed statistics of arrival times that arise from either the usual (convective) quantum flux or from semiclassical considerations suggests testing the notable deviations in an arrival time experiment, thereby probing the predictive power of Bohmian trajectories. The suggested experiment, including the preparation of the wave functions, could be done with present-day experimental technology. [mehr]
Trapped ions are ideal candidates for engineering quantum systems with individual resolution. Qubits are encoded with the internal levels of the ions, and controlled with laser-driven interactions. Such a system present an excellent coherence time and can find wide applications in quantum simulations and quantum computing. [mehr]

From Levitated Nanomagnets to Quantum Magnonics (Cosimo Carlo Rusconi)

From Levitated Nanomagnets to Quantum Magnonics (Cosimo Carlo Rusconi)
In this talk, I will present our results concerning how to describe and use the quantum degrees of freedom of a levitated nanomagnet. [mehr]

Quantum anomaly and transport in the 2D Fermi gas

Quantum anomaly and transport in the 2D Fermi gas
A scale invariant system looks similar on different length scales. Usually this is realized only after some fine tuning, for instance near a phase transition or a scattering resonance. Remarkably, a classical gas in two dimensions is scale invariant for an arbitrary strength of contact interaction. This has striking consequences for its nonequilibrium scaling dynamics, in particular the breathing motion in a harmonic trapping potential. [mehr]
The new idea consists in exploiting the optical field itself to control the properties of crystals and nanostructures. With this approach, it becomes possible to access phenomena occurring within an oscillation of light as benchmarked by three experiments. [mehr]
How does classical chaos affect the generation of quantum entanglement? What signatures of chaos exist at the quantum level and how can they be quantified? [mehr]
We consider two-dimensional weakly-bound heterospecies molecules formed in a Fermi-Bose mixture with attractive Fermi-Bose and repulsive Bose-Bose interactions. [mehr]
From quark and nuclear matter down to solid-state systems and ultracold gases, mass asymmetry is known to profoundly influence the behavior of strongly interacting mixtures of fermionic particles, both at the few- and many-body level. [mehr]
In two dimensions, Projected Entangled-Pair States (PEPS) are elegant many-body wavefunctions which capture efficiently the quantum entanglement of ground states of local quantum spin Hamiltonians. [mehr]
A variety of interesting physical phenomena related to modern optics research will be discussed. [mehr]
We model quantum transport through small interfaces weakly-coupled to two many-body leads under the Born approximation. [mehr]
“Finishing touch“ for your proposal ---- please register at eubuero-bayern@mpq.mpg.de [mehr]

Laboratory Study of Interstellar Ion-Polar Molecule Reactions (Prof. Kunihiro Okada)

Ion-molecule reactions play important roles in the production processes of interstellar molecules in molecular clouds. In this seminar, I will present the recent experimental data on the translational and rotational temperature dependence of the reaction-rate constant in the CH3CN-Ne+ reaction system. [mehr]

Nonlinear Optics with Rydberg Excitons (V. Walther)

The realization of exciton polaritons -- hybrid excitations of semiconductor quantum well excitons and cavity photons -- has been of great technological and scientific significance. [mehr]

A programmable quantum computer based on trapped ions (Dr. N. Linke)

Trapped ions are a promising candidate system to realize a scalable quantum computer. We present a modular quantum computing architecture comprised of a chain of 171Yb+ ions with individual Raman beam addressing and individual readout. [mehr]
Given a space bipartition (A, B) of a quantum state, the entanglement Hamiltonian of A is the logarithm of the reduced density matrix obtained after tracing over B. [mehr]

IMPRS-QST Career Talk (Dr. Enno Aufderheide)

Furthering your career: [mehr]
Recently we have predicted a new quasiparticle - the angulon - which is formed when a quantum impurity (such as an electron, atom, or molecule) exchanges its orbital angular momentum with a many-particle environment (such as lattice phonons or a Fermi sea). [mehr]
In this presentation I will focus on discussing the interplay of Coulomb interactions and weak disorder in atomically thin two-dimensional semiconductors. [mehr]

IMPRS-APS Monthly Talk/ Solids in Ultrafast Strong Fields: Topological Attosecond Phenomena (Prof. Mark Stockmann)

We present our latest results for a new class of quantum phenomena in condensed matter nanooptics when a strong, single-oscillation optical field ∼1 V/Å induces changes in a solid, which are defined by its topological properties. [mehr]

Using macroscopic quantum systems as detectors (Prof. Swati Singh)

When properly engineered, simple quantum systems such as harmonic oscillators or spins can be excellent detectors of feeble forces and fields. [mehr]

The 14th Workshop on Numerical Ranges and Numerical Radii

Program: [mehr]

Lycurgus cup, one of the oldest nanotechnology artifacts (Andrea Benfenati)

Bosonic mixtures in two dimensions (Volker Karle)

From Newton Nonlocality to Quantum Teleportation (Prof. N. Gisin)

To have an object disappearing from one location, only to reappear somewhere else, without the object ever passing through any intermediate locations, is that possible? [mehr]

Black-body radiation and the forgotten heritage of Max Planck (Prof. S. Varró)

Besides the discovery of the fourth fundamental physical constant h, Max Planck (1858-1947) has solved various important problems in physics. [mehr]

The Art of Presenting Science: Discovering the First Law of Stage Acting (Gijs Meeusen)

In this meeting, we will analyse presenting and performance and develop a model of communication that allows you to substantially improve the way you present. [mehr]

High-performance near- and mid-infrared crystalline coatings (Prof. M. Aspelmeyer)

Substrate-transferred crystalline coatings exploit the unique properties of single-crystal semiconductor coatings for high-end laser optics applications. [mehr]
We will inform you about funding opportunities for individual researchers within the European Research Framework Programme Horizon 2020, particularly about the Marie Sklodowska Curie Fellowships and the European Research Council Grants (ERC). PhD students are also very welcome to join! [mehr]

Topological effects in dissipative quantum systems (Marcel Wagner)

The concept of topological order seems to be understood on a high level in dissipation-free quantum systems, i.e. in absence of a reservoir or bath. [mehr]
Detailed program with list of speakers [mehr]

Symmetry reduction induced by anyon condensation: a tensor network approach (José Garre Rubio)

Topological ordered phases are related to changes in the properties of their quasi-particle excitations (anyons). [mehr]

Designing quantum spin-orbit-coupled materials: a source for exotic excitations (Prof. Roser Valenti)

In the search for novel materials' properties, the generation and manipulation of highly entangled quantum states is a grand challenge of solid state research. [mehr]

The emergence of contractility in biological fiber networks (Dr. P. Ronceray)

Large-scale force generation is essential for biological functions such as cell motility, embryonic development, and muscle contraction. [mehr]

Acoustic Control of Light and Matter on a Chip (Prof. H. Krenner)

Phonons, the quanta of mechanical vibrations mediate the propagation of sound and heat in condensed matter. [mehr]

Nonreciprocity and modulation in optomechanics (Dr. Daniel Malz)

Nonreciprocal devices such as circulators or isolators are essential devices in signal processing. [mehr]

Dipolar quantum gases and liquids (Prof. T. Pfau)

Dipolar interactions are fundamentally different from the usual van der Waals forces in real gases. [mehr]

Quantum key distribution networks and their applications for blockchain technologies (A. Fedorov)

The blockchain is a distributed ledger platform with high Byzantine fault tolerance, which enables achieving consensus in a large decentralized network of parties who do not trust each other. [mehr]

PostDoc Talks - Max Planck Harvard Research Center for Quantum Optics

The MPHQ has organized a series of postdoc talks. [mehr]

Polaron physics with ultracold atoms and beyond (Dr. R. Schmidt)

When an impurity is immersed into an environment, it changes its properties due to its interactions with the surrounding medium. [mehr]

Strongly Correlated Systems of Bosons and Fermions: Many-body phenomena and Numerical Methods (Dr. A. Angelone)

Many interesting physical phenomena are connected to strongly correlated systems, which, due to their complexity, cannot usually be studied analitically, making numerical approaches essential. [mehr]

Operational entanglement measures and state transformations (Katharina Schwaiger, MSc)

Entanglement is the resource to overcome the natural limitations of spatially separated parties restricted to Local Operations assisted by Classical Communication (LOCC). [mehr]

Relativistic dynamical reduction models: an overview of the latest results (T. Guaita)

The dynamical reduction program is an attempt to modify the laws of quantum mechanics in order to solve the measurement and macro-objectification problems. [mehr]

Excitation basis for gauge models of topological phases (Dr. C. Delcamp)

The lattice Hamiltonian of Kitaev’s model yields electric and magnetic excitations located at punctures. [mehr]

Quantum storage of multi-mode entanglement based on cold atomic ensembles (Dr. W. Zhang)

Multi-mode entanglement enables quantum communication with higher channel capacity and more efficient quantum-information processing and also is compatible with diverse quantum networks. [mehr]

One, Two, Many Modes: Developent & Application of High-dimensional Systems for Quantum Information Science (Dr. R. Kruse)

In recent years, one of the main quests in quantum optics has been to finally show that quantum-enhanced applications surpass their classical counterparts. [mehr]

Nonequilibrium Quantum States from Integrability (L. Piroli)

Integrable systems display exceptional features when brought out of equilibrium. [mehr]

Improved sensitivity to the electron´s electric dipole moment using YbF molecules (Dr. I. Rabey)

It is well known that the electron has a magnetic dipole moment. [mehr]

Symposium: Gender and Physics?

  • 14:45h talk by Prof. T. Brage "What does Gender have to do with Physics?"
  • Datum: 29.09.2017
  • Uhrzeit: 14:00 - 16:30
  • Vortragende(r): Professor Tomas Brage
  • Department of Physics, Director of Education at Undergraduate Programme of Studies within Faculty of Science, Lund University, Sweden
  • Raum: New Lecture Hall, Room B 0.32
  • Gastgeber: MPQ
Agenda: 14:00h: Gender Equality at the MPQ (Frauke Logermann) - 14:15h: Equal Opportunities in the Max Planck Society (Dr. U. Weber) - 14:30h: The GENERA Project (Nicole Oetke) - 14:45h: Prof. T. Brage - 15:45h: Discussion [mehr]

Quantum simulating gauge theories with discrete-time quantum walks (Dr. P. Arnault)

Quantum walks (QWs) are models of quantum transport on discrete backgrounds, such as graphs or regular lattices. [mehr]

Non-Standard Bose-Hubbard Model with State-Dependent Tunneling (D. González Cuadra)

Non-standard Bose-Hubbard models are relevant for the study of strongly correlated quantum physics thanks to their rich phase diagram and the possibility to simulate them using ultracold atoms in optical lattices. [mehr]

Solving the pentagon equation with trivalent categories (R. Wolf)

Anyons are two-dimensional quasiparticles with exotic statistics that can be used for topological quantum computation. What makes them interesting for this is the concept of fusion and braiding. [mehr]
To thermodynamically address quantum nanoscopic scenarios that involve very small thermal baths and strong system-bath correlation, we suggest a new framework that is based on the principle of passivity. [mehr]
Quantum light-matter interfaces that reversibly map photonic quantum states onto atomic states, are essential components in the quantum engineering toolbox with applications in quantum communication, computing, and quantum-enabled sensing. [mehr]

Doped resonating valence bond states: a quantum information study (Dr. S. Singha)

Resonating valence bond states have played a crucial role in the description of exotic phases in strongly correlated systems, especially in the realm of Mott insulators and the associated highTc superconducting phase transition. [mehr]

Anomalies and entanglement renormalization (Jacob Bridgeman)

We study 't Hooft anomalies of discrete groups in the framework of (1+1)-dimensional multiscale entanglement renormalization ansatz states on the lattice. [mehr]

Tensor Network algorithms to study 1D and 2D quantum matter (A. Kshetrimayum)

Tensor Network (TN) algorithms have become increasingly popular in the study of quantum many-body systems recently. ... [mehr]

Detection of Zak phases and topological invariants in a chiral quantum walk of twisted photons (Dr. A. Dauphin)

Initially discovered in condensed matter, topological phases have so far been simulated in a variety of synthetic systems (ultracold atoms in optical lattices, photonic bandgap materials, mechanical systems, ...). [mehr]

Representations in deep learning and quantum many-body physics (Dr. P. Wittek)

Representation is of central importance in both quantum many-body physics and machine learning. [mehr]

Non-linear response in extended systems: a real-time approach (Dr. C. Attaccalite)

I will present a new formalism to study linear and non-linear response in extended systems. Our approach is based on real-time solution of an effective Schrödinger equation. [mehr]

A Projector Quantum Monte Carlo Method for non-linear wavefunctions (L. Schwarz)

The projected imaginary time evolution of Full Configuration Inter-action Quantum Monte Carlo (FCIQMC) can be reformulated in terms of a Lagrangian minimization which naturally admits polynomial complex wavefunction parameterizatons, thereby circumventing the exponential scaling of the FCIQMC approach. [mehr]

Computational power of symmetry-protected topological phases (D. Stephen)

In many-body physics, many essential properties of a quantum state are determined by the phase of matter in which it resides. Recent years have witnessed tremendous progress in the discovery and classification of quantum phases, and it is thus pertinent to ask: what can a phase of matter be used for? [mehr]

Quantum steerability as a nesting problem (Dr. C. Nguyen)

We are to discuss quantum steerability, which was recently discovered as the third type of quantum nonlocality besides quantum nonseparability and Bell nonlocality. [mehr]

Freewheeling across laser’s wonderland: from mid-infrared filaments to neurophotonics (Prof. A. Zheltikov)

With empowering inspiration from multidisciplinary activities of the MPQ/MAP/CALA constellation, this talk will undertake an adventure of a freewheeling tour over wildly different landscapes of laser’s wonderland. [mehr]

Synthetic gauge fields: from topology to the Unruh effect (A. Celi)

The theoretical and experimental progress in quantum simulation with ultracold atoms of the last decay have pushed the realm of simulable models well deep into condensed matter and has started touching high-energy and gravitational physics. [mehr]

High-Fidelity Hot Gates for Generic Spin-Resonator Systems (Dr. M. Schütz)

We propose and analyze a high-fidelity hot gate for generic spin-resonator systems which allows for coherent spin-spin coupling, in the presence of a thermally populated resonator mode. [mehr]

Decoding Protocols for Classical Communication on Quantum Channels (M. Rosati)

I discuss the transmission of classical information via quantum carriers with focus on the decoding stage. [mehr]

Quantum optomechanics with superfluid helium density waves (Alexey Shkarin)

The field of optomechanics deals with the interaction between light and mechanical objects. [mehr]

DMRG with Subspace Expansion on Symmetry-Protected Tensor Networks (C. Hubig)

The Density Matrix Renormalisation Group when applied to matrix-product states is the method of choice for ground-state search on one-dimensional systems and still highly competitive even in unfavourable circumstances, such as critical systems and higher dimensions. [mehr]
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Quantum optics with semiconductor quantum dots (Prof. P. Senellart-Mardon)

Today, optical quantum technologies are limited both by the low efficiency of heralded single-photon sources and by the probabilistic operation of two-photon gates. [mehr]

Efficient representation of fully many-body localized systems using tensor networks (Dr. T. Wahl)

Many-body localization (MBL) is currently an intensely studied topic and characterized by the fact that certain strongly disordered systems fail to thermalize. For sufficiently strong disorder in one dimension, all eigenstates of MBL systems fulfill the area law of entanglement. [mehr]

Silicon-Based Microresonator Frequency Combs (Prof. A. Gaeta)

Microresonator frequency combs have attracted much recent interest due to their potential to enable time and frequency metrology applications in a highly compact and robust platform. [mehr]

From cold atoms to ultracold molecules: spin‐wave rephasing and ultracold exchange reaction (Dr. Jun Rui)

In this talk, I will introduce the setup that we have built in the past three years to create ultracold 23Na40K molecules from an ultracold atomic mixture gas. [mehr]

Nonlinear Optics with Metals (Dr. S. Gennaro)

A recurring theme in optics and photonics is the ability of metal nanostructures to imbue man – made material (so – called metamaterial) with new functions possibly not found in nature. [mehr]

Variational Energy Minimization for Continuous Matrix Product States (Dr. M. Ganahl)

The generalization of Matrix Product States (MPS) to continuous systems, as proposed in Phys. Rev. Lett. 104, 190405(2010), provides a powerful variational ansatz for the ground state of strongly interacting quantum field theories in one spatial dimension. [mehr]

Majorana quasi-particles from angular momentum conservation (Dr. F. Iemini)

We show how angular momentum conservation can stabilise a quasi-topological phase of matter supporting Majorana qausi-particles as edge modes. [mehr]

Characterizing many-body states at finite temperature via a Klein twist (Dr. H.-H. Tu)

In this talk, I will describe an ongoing work on how universal data for distinguishing different phases may be extracting from thermal states of quantum many-body systems. [mehr]

Non-adiabatic effects in laser orientation ad alignment of molecules (Prof. González Férez)

We present a theoretical study of the laser-alignment and mixed-field-orientation experiments of polar molecules. [mehr]

LAP Meeting - "Translational Ultrasmall Particle Imaging Tools for Molecular Cancer Imaging and Treatment"

Advances in nanotechnology have fueled a paradigm shift in targeting and safely delivering peptide/proteins and drugs in conjunction with image-directed approaches. [mehr]

Quantum chaos, thermalization, and many-body Anderson localization (Prof. David A. Huse)

Bipartite charge fluctuations in Z_2 topological insulators and superconductors (Dr. L. Herviou)

Bipartite charge fluctuations (BCF) have been introduced to provide an experimental indication of many-body entanglement. They are a very efficient and useful tool to characterize phase transitions in a large variety of charge-conserving models in one and two dimensions. ... [mehr]
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Non-symmorphic route to nodal semimetals (Tomas Bzdusek)

Nodal semimetals are materials in which the conduction and the valence bands touch at points or lines in the Brillouin zone. Such nodal band structures manifest themselves in unusual transport phenomena as well as in topologically protected surface states. ... [mehr]

Understanding Contextuality as a Quantum Computational Resource without Wigner Functions (Dr. J. Bermejo-Vega)

A central question in quantum computation is to identify the resources that are responsible for quantum speed-up. Quantum contextuality has been recently shown to be a resource for quantum computation with magic states for odd-prime dimensional qudits and two-dimensional systems with real wavefunctions. ... [mehr]
This talk aims to offer insight into the latest developments at the APS Editorial Office and its flagship publication. [mehr]
The Quantum Community in Munich launches its International Max Planck Research School for Quantum Science and Technology (IMPRS-QST). To this end, we celebrate the IMPRS Launch with several Quantum talks on Thursday at the Herbert Walther lecture hall (MPQ,Garching). On Friday afternoon, our members from the Walther-Meissner Institute will present their work on the MQC Workshop together with a subsequent poster session. [mehr]
Cold atoms can now be routinely prepared and precisely controlled for the study of quantum physics. [mehr]
Tests of quantumness are experiments which enable us to exclude the possibility of modeling them with classical means. They enable us to prove strong statements about the nature of the universe and obtain cryptographic protocols with an unprecedented level of security. [mehr]
Trapping ultracold atoms in optical lattices enabled numerous breakthroughs uniting several disciplines. Although light is a key ingredient in such systems, its quantum properties are typically neglected, reducing its role to a classical tool for atom manipulation. [mehr]
I will discuss two research lines I'm developing. [mehr]
Many large-scale, universal, effects in one-dimensional systems at quantum critical points can be tackled with a combination of methods from solvable lattice models and from field theory, usually conformal field theory (CFT) and Luttinger liquid ideas. [mehr]
Many-body systems with both coherent dynamics and dissipation constitute a rich class of models which are nevertheless much less explored than their dissipationless counterparts. The advent of numerous experimental platforms that simulate such dynamics poses an immediate challenge to systematically understand and classify these models. [mehr]
In the present talk I will give an overview on the physics of 2-component Bose gases in presence of a spin exchange Rabi term. [mehr]
The ability to manipulate molecules with electric fields offers new opportunities for studying cold collisions and performing precision tests. [mehr]
In order to increase the electron energy gain by the laser wakefield acceleration (LWFA), three ways are known. The first way is to multi-stage the LWFA beyond the dephasing length. The second method is to decrease the plasma density so that the dephasing length is increased. [mehr]
In 2010 the first measurement of the proton charge radius from spectroscopy of muonic hydrogen was found to be five standard deviations away from the regular hydrogen value. [mehr]
The Abelian Higgs model in 1 space and 1 time dimensions has important features in common with models relevant for high energy physics: confinement and existence of topological solutions of the classical equations of motion. [mehr]
The way in which quantities such as energy, classical and quantum information, and entanglement propagate through extended systems is of great interest from quantum field theory to condensed matter systems. [mehr]
Microfabricated surface traps enable a wide range of trapping geometries and provide a scalable platform for trapped ion Quantum Information Processing (QIP). [mehr]
Dynamical phase transitions can occur in isolated quantum systems that are brought out of equilibrium by either a sudden or a gradual change of their parameters. [mehr]
Quantum optics and many-body physics increasingly merge together in ultracold atomic gases and certain classes of solid state systems. This gives rise to new non-equilibrium scenarios even in stationary state, where coherent and dissipative dynamics appear on an equal footing. [mehr]
Atomic gases at ultralow temperatures prepared in optical lattice potentials provide an exquisite platform to study many-body quantum systems out of equilibrium. [mehr]
Casimir-Polder forces and their consequences: from matter-wave scattering in complex geometries to CP violation and quantum friction Casimir-Polder forces between a single atom and a macroscopic body are effective electromagnetic interactions that may be attributed to the vacuum fluctuations of the electromagnetic field. [mehr]
In this talk, I will discuss our progress in the development of a two-photon laser-cooling scheme for hydrogen.  [mehr]
In the last few years there has been an increasing interest in the potential of quantum improvements in machine learning (ML) and artificial intelligence (AI). [mehr]
Since the discovery of the vapor-liquid-solid (VLS) mechanism for semiconductor nanowire (NW) growth over 50 years ago, semiconductor NWs have been a widely studied technology in various areas including photonics, plasmonics, and electronics. [mehr]
When a quantum system is subjected to a continuous measurement, its evolution becomes stochastic and in a proper limit, it can be described by a continuous equation with Gaussian noise. [mehr]
The fractional quantum Hall effect is the most celebrate example of a two-dimensional phase that exhibits intrinsic topological order. [mehr]
Deep insights into the structure of a many-body state can often be inferred from its natural orbitals (eigenvectors of the reduced one-body density operator) and their populations. [mehr]
We consider a thought experiment where the preparation of a macroscopically massive or charged particle in a quantum superposition and the associated dynamics of a distant test particle apparently allow for superluminal communication. [mehr]
Spectroscopic analysis allows for the label-free objective classification of biological material on the molecular scale. This technique has been applied to histology, cytology and surgical pathology and can detect subtle changes in the proteome and metabolome. [mehr]
Patterning surfaces with subwavelength spaced metallo-dielectric features (metasurfaces) allows one to generate complex 3D and 2D wavefronts by locally controlling the amplitude, phase and polarization of the scattered light. [mehr]
The radius of the proton, generally assumed to be a well measured and understood  quantity has recently come under scrutiny due to highly precise, yet conflicting, experimental results. These new results have generated a host of interpretations, none of which are completely satisfactory. [mehr]
Large spin systems can exhibit unconventional types of magnetic ordering different from the ferromagnetic or N\'eel-like antiferromagnetic order commonly found in spin 1/2 systems. [mehr]
The quantum cascade laser has demonstrated the ability to provide gain over a very broad wavelength range. [mehr]
Photonic entanglement is one of the most common methods to generate and study entangled states. Photon pairs can be entangled in different degrees freedom including polarisation, momentum or energy. [mehr]
If a polarization excess is injected in many-spin quantum system which is initially in a high-temperature equilibrium, then this “excitation” would spread all over as consequence of spin-spin interactions. [mehr]

WORKSHOP "Future of ultrashort pulses"

The availability of waveform-controlled, intense, few cycle laser fields has radically expanded the ability of scientists to peer into the dynamics of atoms and solids on few-femtosecond or even attosecond time scales. This research in the field of attosecond science has hinted at the potential for new discoveries that may be unlocked by new developments in laser science to confine more and more energy into smaller and smaller packages to be precisely delieved to the systems under study. [mehr]
It was long considered a practical impossibility to extend the methods of laser cooling and trapping to diatomic molecules. [mehr]
Quantum correlations are strongly enhanced near quantum critical points, which opens attractive prospects for applications such as quantum-enhanced metrology. [mehr]
The active laser cavity can be considerably more sensitive than a passive one to minute perturbations. The difference in sensitivity between passive and active resonator sensors is akin to forensic dissection as compared to vivisection. [mehr]
“We propose to use Quantum Hall edge channels in order to generate long-range entanglement between spatially separated spin qubits. Since the entanglement is actively stabilized by purely dissipative dynamics, our scheme is inherently robust against noise and imperfections.” [mehr]
A new frontier of extreme light at Exawatt level is discussed. This frontier has approached to us much closer than we thought till only recently. [mehr]
A 3-mode optomechanical system (e.g., with two electromagnetic fields coupled to a single mode of a mechanical resonator) is a key element of hybrid quantum systems. [mehr]
Several types of quantum-dot spin valves were recently realized. For such systems, we have analyzed the efficient transfer of angular momentum into the nuclear bath and the detection of nuclear-spin coherence through transport signatures. [mehr]
In recent years, systems of ultracold atoms in optical lattices have opened new opportunities for exploring time-dependent many-body dynamics. [mehr]
Interactions between light and matter lie at the heart of optical communication and information technology. [mehr]
The main focus of this edition of the Symposia on Topological Quantum Information will be the realization of topological phases of matter in cold-atom setups. The Symposium will be mainly aimed to PhD students and postdocs working in this field. [mehr]
Nitrogen-vacancy (NV) center is one of the most promising systems for quantum information processing. [mehr]
The strong interactions of elementary particles are described theoretically in the framework of Quantum Chromodynamics (QCD). [mehr]
We give restrictions on locality-preserving unitary automorphisms U, which are protected gates, for 2-dimensional topologically ordered systems. [mehr]
Traditional thermodynamics deals with macroscopic systems in thermal equilibrium, where one only has control over a few macroscopic variables (volume, temperature, etc). [mehr]
We study impure mesoscopic one-dimensional ensembles with majority particles either non-interacting fermions or bosons. [mehr]
Black holes are one of the most mysterious concepts in physics and carry with them a large number of unsolved problems and counterintuitive results, none of which are more troubling than the information paradox. [mehr]
We examine the response of a system localized by disorder to a time dependent local perturbation which varies smoothly with a characteristic timescale τ. [mehr]
I will discuss several cases where far out of equilibrium dynamics of many-body systems gives rise to emergent quasistationary states, that can be loosely termed as prethermalized. [mehr]
Spectroscopy with terahertz (THz) fields is rapidly developing into a highprecision instrument that is able to characterize and steer quantum processes in semiconductors. [mehr]
In recent years, quantum fluids of light in nonlinear optical systems have attracted a considerable interest [1]. [mehr]
The fundamental mechanism underlying harmonic emission in the strong-field regime is governed by tunnel ionization of the atom, followed by the motion of the electron wave packet in the continuum, and finally by its recollision with the atomic core. [mehr]
Spectral and topological properties of bands, such as the curvature andBerry curvature, have dynamical significance. [mehr]
The conductance of a quantum point contact exhibits an unexpected shoulder at $simeq 0.7 (2 e^2/h)$, known as the "0.7-anomaly", whose origin is still subject to debate. [mehr]
I will present recent experimental activities in the field of cold atoms taking place at Institute of Physics in Zagreb. [mehr]
Recently tensor network (TN) methods have been extended so to better address lattice gauge theories (LGT). [mehr]
At the heart of quantum mechanics lies the fact that a measurement causes back-action on the system itself. [mehr]
Ultracold mixtures hold the promise of understanding new phases of matter and collisions at very low energies. [mehr]
Cold and ultracold molecules possess the potential to revolutionize physical chemistry and few-body physics, provide new techniques for probing new states of quantum matter, allow for precision measurements of both fundamental and applied interest and enable quantum simulations of condensed matter phenomena. [mehr]
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