Ultrastrong coupling is a distinct regime of electromagnetic interaction that enables rich variety intriguing physical phenomena. Traditionally, this has been reached by intersubband transitions multiple quantum wells, superconducting artificial atoms, or two-dimensional electron gases to microcavity resonators. However, employing these platforms requires demanding experimental conditions such as cryogenic temperatures, strong magnetic fields, and high vacuum. Here, we use plasmonic nanorods...

Ultrastrong coupling (USC) is a distinct regime of light-matter interaction in which the strength comparable to resonance energy cavity or emitter. In USC regime, common approximations quantum optical Hamiltonians, such as rotating wave approximation, break down ground state coupled system gains photonic character due admixing vacuum states with higher excited states, leading ground-state changes. usually achieved by collective coherent many emitters single mode cavity, whereas molecule...

We derive an adiabatic technique that implements the most general SU($d$) transformation in a quantum system of $d$ degenerate states, featuring qudit. This is based on factorization into generalized Householder reflections, each which implemented by two-shot stimulated Raman passage with appropriate static phases. The energy lasers needed to synthesize single reflection shown be remarkably constant as function $d$. directly applicable linear trapped ion $d+1$ ions. implement Fourier...

We show that the interaction of surface plasmons with quantum emitters can be described by an effective model has same structure as a lossy multimode cavity electromagnetic interaction. This allows coherent manipulation dressed at nanoscale. strong coupling in plasmonics used to mediate efficiently between via decoherence-free channel, immune plasmon dissipation. Efficient and robust population transfer, well deterministic generation entanglement are numerically shown. These results pave way...

Realizing strong coupling between a single quantum emitter (QE) and an optical cavity is of crucial importance in the context various applications. Although Rabi splitting emitters coupled to high-$Q$ classical cavities has been reported numerous configurations, attaining with plasmonic nanostructure remains challenge. In particular, at QE regime would open path for realization single-photon nonlinearities. this paper, we derive plasmon quantization procedure systems consisting located gap...

Hybrid molecule-plasmonic nanostructures have demonstrated their potential for surface enhanced spectroscopies, sensing, or quantum control at the nanoscale. In this Letter, we investigate strong coupling regime and explicitly describe hybridization between localized plasmons of a metal nanoparticle excited state emitter, offering simple precise understanding energy exchange in full analogy with cavity electrodynamics treatment dressed atom picture. Both near-field emission far-field...

We derive effective Hamiltonians for a single dipolar emitter coupled to metal nanoparticle (MNP) with particular attention devoted the role of losses. For small particles sizes, absorption dominates and non-hermitian Hamiltonian describes dynamics hybrid emitter-MNP nanosource. discuss system in weak strong coupling regimes offering simple understanding energy exchange, including radiative non-radiative processes. define plasmon Purcell factors each mode. large particle leakages can...

We propose a geometry-specific, mode-selective quantization scheme in coupled field-emitter systems which makes it easy to include material and geometrical properties, intrinsic losses as well the positions of an arbitrary number quantum emitters. The method is presented through example spherically symmetric, non-magnetic, arbitrarily layered system. follow up by framework project system on simpler, effective cavity QED models. Maintaining well-defined connection original quantization, we...

Strong coupling between a single quantum emitter and an electromagnetic mode is one of the key effects in optics. In cavity QED approach to plasmonics, strongly coupled systems are usually understood as single-transition emitters resonantly radiative plasmonic mode. However, cavities also support non-radiative (or "dark") modes, which offer much higher strengths. On other hand, realistic often multiple electronic transitions various symmetry, could overlap with order -- blue or ultraviolet...

Over the last decades, quantum optics has evolved from high-quality-factor cavities in early experiments toward new cavity designs involving leaky modes. Despite very reliable models, concepts of electrodynamics, photon leakage is most time treated phenomenologically. Here, we take a different approach, and starting first principles, define an inside-outside representation which derived original true-mode representation, one can determine effective Hamiltonian Poynting vector. Unlike...

The interaction between superconducting qubits and one-dimensional microwave transmission lines has been studied experimentally theoretically in the past two decades. In this work, we investigate spontaneous emission of an initially excited artificial atom which is capacitively coupled to a semi-infinite line, shorted at one end. This configuration can be viewed as front mirror. distance mirror introduces time delay system, take into account fully. When equals integer number oscillation...

In this paper, we investigate the dynamics of a single superconducting artificial atom capacitively coupled to transmission line with characteristic impedance comparable or larger than quantum resistance. regime, microwaves are reflected from also at frequencies far atom's transition frequency. Adding mirror in then creates cavity modes between and mirror. Investigating spontaneous emission atom, find Rabi oscillations, where energy oscillates one modes.Received 8 December 2020Accepted 11...

Recent technological advancements have enabled strong light-matter interaction in highly dissipative cavity-emitter systems. However, these systems, which are well described by the Tavis-Cummings model, considerable loss rates render realization of many desirable nonlinear effects, such as saturation and photon blockade, problematic. Here we present another effect occurring within model: A response cavity for resonant external driving intermediate strength, makes use large dissipation rates....

Ultrastrong coupling between optical and material excitations is a distinct regime of electromagnetic interaction that enables variety physical phenomena. Traditional ways to ultrastrong light-matter involve the use some sorts quantum emitters, such as organic dyes, wells, superconducting artificial atoms, or transitions two-dimensional electron gases. Often, reaching requires special conditions, including high vacuum, strong magnetic fields, low temperatures. Recent reports indicate degree...

The optical response of a matter excitation embedded in nanophotonic devices is commonly described by the Drude-Lorentz model. Here, we demonstrate that this widely used approach fails case where quantum-confined plasmons two-dimensional electron gas interact strongly with phonons. We propose new quantum model which contains semiclassical one for simple electronic potentials, but predicts very different results symmetry-broken potentials. unveil mechanism oscillator strength transfer between...

Unlocking the full potential of nanophotonic devices involves engineering their intrinsic optical properties. Here, authors investigate a quantum theory that treats interaction between quantum-confined plasmons and phonons in semiconductors. This allows computation response beyond conventional Drude-Lorentz model. In particular, it predicts new effects, such as an oscillator-strength transfer mechanism dark plasmon modes.

The quantum control of emitters is a key issue for information processing at the nanoscale. This generally necessitates strong coupling to high Q-cavity efficient manipulation atoms and field dynamics (cavity electrodynamics or cQED). Since almost decade, efforts are put transpose cQED concepts plasmonics in order profit mode confinement surface plasmons polaritons. Despite intrinsic presence lossy channels leading decoherence systems, it has been experimentally proven that possible reach regim [1].

Ultrastrong coupling between optical and material excitations is a distinct regime of electromagnetic interaction that enables variety intriguing physical phenomena. Traditional ways to ultrastrong light-matter involve the use some sorts quantum emitters, such as organic dyes, wells, superconducting artificial atoms, or transitions two-dimensional electron gases. Often, reaching domain requires special conditions, including high vacuum, strong magnetic fields, extremely low temperatures....

Recent technological advancements have enabled strong light-matter interaction in highly dissipative cavity-emitter systems. However, these systems, which are well described by the Tavis-Cummings model, considerable loss rates render realization of many desirable nonlinear effects, such as saturation and photon blockade, problematic. Here we present another effect occurring within model: a response cavity for resonant external driving intermediate strength, makes use large dissipation rates....