We study the driven-dissipative dynamics of a network spin-1/2 systems coupled to one or more chiral 1D bosonic waveguides within framework Markovian master equation. determine how interplay between coherent drive and collective decay processes can lead formation pure multipartite entangled steady states. The key ingredient for emergence these many-body dark states is an asymmetric coupling spins left right propagating guided modes. Such are motived by experimental possibilities with...

We consider the non-equilibrium dynamics of a driven dissipative spin chain with chiral coupling to 1D bosonic bath, and its atomic implementation two-species mixture cold quantum gases. The reservoir is represented by spin-orbit coupled quasi-condensate atoms in magnetized phase, while spins are identified motional states separate species an optical lattice. chirality excitations allows couple differently left right moving modes, which our setup can be tuned from bidirectional purely...

We propose to use the intrinsic two-level system (TLS) defect states found naturally in integrated optomechanical devices for exploring cavity QED-like phenomena with localized phonons. The Jaynes-Cummings-type interaction between TLS and mechanics can reach strong coupling regime existing nano-optomechanical systems, observable via clear signatures output spectrum. These persist even at finite temperature, we derive an explicit expression temperature which they vanish. Further, ability...

We study the dynamics of chiral quantum networks consisting nodes coupled by unidirectional or asymmetric bidirectional channels. In contrast to familiar photonic where driven two-level atoms exchange photons via 1D nanostructures, we propose and a setup interactions between are mediated spin excitations (magnons) in $XX$ chains representing waveguides. While Markovian network theory eliminates channels as structureless reservoirs Born-Markov approximation obtain master equation for nodes,...

A new qubit readout scheme preserves quantum state probabilities while maximizing fidelity with a fast time, thus providing robust measurement method for generation of superconducting processors.

Coherent photon-emitter interfaces offer a way to mediate efficient nonlinear photon-photon interactions, much needed for quantum information processing. Here we experimentally study the case of two-level emitter, dot, coupled single optical mode in nanophotonic waveguide. We carry out few-photon transport experiments and record statistics light reconstruct scattering matrix elements one- two-photon components. This provides direct insight complex photon interaction that contains rich...

We present a topological approach to the input-output relations of photonic driven-dissipative systems acting as directional amplifiers. Our theory relies on mapping from optical non-Hermitian coupling matrix an effective insulator Hamiltonian. This is based singular value decomposition matrices, inverse which determines linear response system. In topologically nontrivial regimes, lattice dominated by vectors with zero values that are equivalent energy states in insulators, leading...

We consider a linear array of trapped ions subjected to local parametric modulation the trapping potential and continuous laser cooling. In our model, phase varies linearly along array, breaking time-reversal symmetry inducing non-trivial topological effects. The response an external force is investigated with Green's function formalism. predict appearance amplification regimes in which ion behaves as directional amplifier vibrational excitations. emergence phases determined by winding...

Engineering deterministic photonic gates with simple resources is one of the long-standing challenges in quantum computing. Here, we design a passive conditional gate between copropagating photons using an array only two-level emitters. The key resource to harness effective photon-photon interaction induced by chiral coupling emitter two waveguide modes different resonant momenta at emitter’s transition frequency. By studying system’s multiphoton scattering response, demonstrate that,...

In a ``chiral'' quantum network, the directionality of emission into photonic waveguides provides new tool to realize communication. Two different architectures with purely atomic are thoroughly investigated as possible building blocks for such networks, providing path implementations within state-of-the-art technology.

Quadratic light-matter interactions are nonlinear couplings such that quantum emitters interact with photonic or phononic modes exclusively via the exchange of excitation pairs. Implementable atomic and solid-state systems, these lead to a plethora phenomena have been characterized in context cavity QED, where localized bosonic modes. Here, we explore quadratic waveguide QED setting, propagating fields confined one-dimensional environment. We develop general scattering theory under Markov...

We study the problem of definition energy-momentum tensor light in general moving non-dispersive media with linear constitutive law.Using basic principles classical field theory, we show that for correct understanding problem, one needs to carefully distinguish situations when material medium is modeled either as a background on which propagates or dynamical part total system.In former case, prove (generalized) Belinfante-Rosenfeld (BR) electromagnetic coincides Minkowski tensor.We derive...

We relate observables in open quantum systems with the topology of non-Hermitian models using Keldysh path-integral method. This allows to extract an effective Hamiltonian from Green's function which contains all relevant topological information and produces $\ensuremath{\omega}$-dependent invariants, linked response functions at a given frequency. Then, we show how detect transition between different phases by measuring local perturbations. Our formalism is exemplified one-dimensional...

An efficient characterization of QND measurements is an important ingredient towards certifying and improving the performance scalability quantum processors. In this work, we introduce a parallel tomography that addresses single- two-qubit readout on multi-qubit processor. We provide experimental demonstration tomographic protocol 7-qubit IBM-Q device, characterizing quality conventional qubit as well generalized such parity or measurement-and-reset schemes. Our reconstructs Choi matrices...

In this work we develop an experimental procedure to interrogate the single- and multiphoton scattering matrices of unknown quantum system interacting with propagating photons. Our proposal requires coherent state laser or microwave inputs homodyne detection at scatterer's output, provides simultaneous information about multiple-elastic inelastic-segments matrix. The method is resilient detector noise its errors can be made arbitrarily small by combining experiments various powers. Finally,...

We propose a realistic setup, inspired by already existing experiments, within which we develop general formalism for the implementation of distributed quantum gates. Mediated link that establishes bidirectional channel between distant nodes, our proposal works both inter- and intranode communication handles scenarios ranging from few to many modes limit link. are able design fast reliable state transfer protocols in every regime operation, which, together with detailed description...

We study the dynamics of up to two Rydberg excitations and correlation growth in a chain atoms coupled photonic crystal waveguide. In this setup, an excitation can hop from one atom another via exponentially decaying exchange interactions mediated by An initially localized undergoes continuous-time quantum walk for short-range hopping, long-range it experiences quasilocalization. addition, inverse participation ratio reveals superballistic diffusion short times, whereas, at long time,...

We introduce a self-consistent tomography for arbitrary quantum nondemolition (QND) detectors. Based on this, we build complete physical characterization of the detector, including measurement processes and quantification fidelity, ideality, backaction measurement. This framework is diagnostic tool dynamics QND detectors, allowing us to identify errors, improve their calibration design. illustrate this realistic Jaynes-Cummings simulation superconducting qubit readout. characterize...

We develop a relativistic variational model for nematic liquid crystal interacting with an electro- magnetic field. The constitutive relation general anisotropic uniaxial diamagnetic and dielectric medium is analyzed. discuss light wave propagation in this moving medium, which the corresponding optical metrics are identified explicitly. A Lagrangian coupled system of electromagnetic field constructed, from complete set equations motion derived. canonical energy-momentum spin tensors...

Quantum microwave photonics aims at generating, routing, and manipulating propagating quantum fields in the spirit of optical photonics. To this end, strong nonlinearities superconducting circuits can be used to either improve or move beyond implementation concepts from domain. In context, design a well-controlled broadband environment for is central task. work, we place transmon qubit one arm an on-chip Mach-Zehnder interferometer composed two beam splitters. By measuring its relaxation...

We develop a theoretical framework to describe the scattering of photons against two-level quantum emitter with arbitrary correlated dephasing noise. This is particularly relevant waveguide-QED setups solid-state emitters, such as superconducting qubits or dots, which couple complex environments in addition propagating along waveguide. Combining input–output theory and stochastic methods, we predict effect single-photon transmission experiments weak coherent inputs. discuss homodyne...

We propose an efficient, scalable, and deterministic scheme to generate multiple indistinguishable photons over independent channels, on demand. Our design relies single-photon sources, each coupled a waveguide, all interacting with common cavity mode. The synchronizes triggers the simultaneous emission of one photon by source, which are collected waveguides. In state-of-the-art circuit QED implementation, this supports creation single <a:math...

Engineering deterministic photonic gates with simple resources is one of the long-standing challenges in quantum computing. Here, we design a passive conditional gate between co-propagating photons using an array only two-level emitters. The key resource to harness effective photon-photon interaction induced by chiral coupling emitter two waveguide modes different resonant momenta at emitter's transition frequency. By studying system's multi-photon scattering response, demonstrate that,...