papers

Publications (95)

cond-mat.mes-hall2012

The Leggett-Garg inequality in electron interferometers

Clive Emary, Neill Lambert, Franco Nori

We consider the violation of the Leggett-Garg inequality in electronic Mach-Zehnder inteferometers. This set-up has two distinct advantages over earlier quantum-transport proposals…

cond-mat.mes-hall2026

Photon-energy-programmable subnanometric electron birth-site control

Hirofumi Yanagisawa, Abhisek Sinha, Ravi Kumar +2

Optical control of electron-generation sites has broadly enabled ultrafast nanoscale imaging, spectroscopy, and functional control. Existing approaches achieve nanoscale site selec…

quant-ph2023

The Closed and Open Unbalanced Dicke Trimer Model: Critical Properties and Nonlinear Semiclassical Dynamics

Cheng Zhang, Pengfei Liang, Neill Lambert +1

We study a generalization of a recently introduced Dicke trimer model [Phys. Rev. Lett. 128, 163601, Phys. Rev. Research 5, L042016], which allows for cavity losses and unbalanced…

quant-ph2017

Temporal Steering in Four Dimensions with applications to coupled qubits and magnetoreception

Huan-Yu Ku, Shin-Liang Chen, Hong-Bin Chen +3

Einstein-Podolsky-Rosen (EPR) steering allows Alice to remotely prepare a state in some specific bases for Bob through her choice of measurements. The temporal analogue of EPR stee…

cond-mat.str-el2026

Exact description of fermionic reservoirs via purified damped ancillary fermions

Pengfei Liang, Neill Lambert, Mauro Cirio

We present a method for the modeling of fermionic reservoirs using a new class of ancillary damped fermions, dubbed purified pseudofermions, which exhibit unusual free correlations…

quant-ph2026

Experimental simulation of postselected closed timelike curves for decoding scrambled quantum information

Yi-Te Huang, Hsiang-Wei Huang, Jhen-Dong Lin +5

Quantum information scrambling (QIS) describes the rapid spread of initially localized information across an entire quantum many-body system through entanglement generation. Once s…

physics.bio-ph2013

Radical-pair model of magnetoreception with spin-orbit coupling

Neill Lambert, Simone De Liberato, Clive Emary +1

The mechanism used by migratory birds to orientate themselves using the geomagnetic field is still a mystery in many species. The radical pair mechanism, in which very weak magneti…

physics.chem-ph2016

Energy transfer in structured and unstructured environments: master equations beyond the Born-Markov approximations

Jake Iles-Smith, Arend G. Dijkstra, Neill Lambert +1

We explore excitonic energy transfer dynamics in a molecular dimer system coupled to both structured and unstructured oscillator environments. By extending the reaction coordinate…

cond-mat.mes-hall2010

Distinguishing quantum and classical transport through nanostructures

Neill Lambert, Clive Emary, Yueh-Nan Chen +1

We consider the question of how to distinguish quantum from classical transport through nanostructures. To address this issue we have derived two inequalities for temporal correlat…

quant-ph2026

Strongly-coupled non-Markovian waveguide QED with input-output HEOM

Neill Lambert, Yi-Te Huang, Yueh-Nan Chen +2

We consider the problem of modeling a single qubit in contact with a one-dimensional waveguide beyond the standard perturbative and Markovian approximations. Using the recently dev…

quant-ph2018

Quantum simulation of photosynthetic energy transfer

Bi-Xue Wang, Ming-Jie Tao, Qing Ai +7

Near-unity energy transfer efficiency has been widely observed in natural photosynthetic complexes. This phenomenon has attracted broad interest from different fields, such as phys…

quant-ph2020

Nonclassical Preparation of Quantum Remote States

Shih-Hsuan Chen, Yu-Chien Kao, Neill Lambert +2

Remote state preparation (RSP) enables a sender to remotely prepare the quantum state of a receiver without sending the state itself. Recently, it has been recognized that quantum…

quant-ph2022

Quantifying Quantumness of Channels Without Entanglement

Huan-Yu Ku, Josef Kadlec, Antonín Černoch +8

Quantum channels breaking entanglement, incompatibility, or nonlocality are defined as such because they are not useful for entanglement-based, one-sided device-independent, or dev…

quant-ph2016

No-cloning of quantum steering

Ching-Yi Chiu, Neill Lambert, Teh-Lu Liao +2

Einstein-Podolsky-Rosen (EPR) steering allows two parties to verify their entanglement, even if one party's measurements are untrusted. This concept has not only provided new insig…

quant-ph2021

General bound on the performance of counter-diabatic driving acting on dissipative spin systems

Ken Funo, Neill Lambert, Franco Nori

Counter-diabatic driving (CD) is a technique in quantum control theory designed to counteract nonadiabatic excitations and guide the system to follow its instantaneous energy eigen…

quant-ph2019

Open quantum systems with local and collective incoherent processes: Efficient numerical simulation using permutational invariance

Nathan Shammah, Shahnawaz Ahmed, Neill Lambert +2

The permutational invariance of identical two-level systems allows for an exponential reduction in the computational resources required to study the Lindblad dynamics of coupled sp…

quant-ph2016

Quantifying Non-Markovianity with Temporal Steering

Shin-Liang Chen, Neill Lambert, Che-Ming Li +3

Einstein-Podolsky-Rosen (EPR) steering is a type of quantum correlation which allows one to remotely prepare, or steer, the state of a distant quantum system. While EPR steering ca…

cond-mat.mes-hall2026

Quantum transport in Cooper pair splitters using hierarchical equations of motion

Riya Baruah, Neill Lambert, Franco Nori +1

We investigate charge transport in Cooper pair splitters beyond the weak-coupling and Markovian limits. To this end, we employ hierarchical equations of motion (HEOM), which can ca…

quant-ph2023

A quantum-classical decomposition of Gaussian quantum environments: a stochastic pseudomode model

Si Luo, Neill Lambert, Pengfei Liang +1

We show that the effect of a Gaussian Bosonic environment linearly coupled to a quantum system can be simulated by a stochastic Lindblad master equation characterized by a set of a…

quant-ph2016

Superradiance with an ensemble of superconducting flux qubits

Neill Lambert, Yuichiro Matsuzaki, Kosuke Kakuyanagi +3

Superconducting flux qubits are a promising candidate for realizing quantum information processing and quantum simulations. Such devices behave like artificial atoms, with the adva…

quant-ph2025

HierarchicalEOM.jl: An efficient Julia framework for hierarchical equations of motion in open quantum systems

Yi-Te Huang, Po-Chen Kuo, Neill Lambert +5

The hierarchical equations of motion (HEOM) approach can describe the reduced dynamics of a system simultaneously coupled to multiple bosonic and fermionic environments. The comple…

cond-mat.mes-hall2009

Detecting Bose-Einstein condensation of exciton-polaritons via electron transport

Yueh-Nan Chen, Neill Lambert, Franco Nori

We examine the Bose-Einstein condensation of exciton-polaritons in a semiconductor microcavity via an electrical current. We propose that by embedding a quantum dot p-i-n junction…

quant-ph2013

Entanglement swapping and testing quantum steering into the past via collective decay

Yueh-Nan Chen, Shin-Liang Chen, Neill Lambert +3

We propose a scheme to realize entanglement swapping via superradiance, entangling two distant cavities without a direct interaction. The successful Bell-state-measurement outcomes…

quant-ph2023

A pseudo-fermion method for the exact description of fermionic environments: from single-molecule electronics to Kondo resonance

Mauro Cirio, Neill Lambert, Pengfei Liang +5

We develop a discrete fermion approach for modelling the strong interaction of an arbitrary system interacting with continuum electronic reservoirs. The approach is based on a pseu…

quant-ph2018

Dynamics of an ultra-strongly-coupled system interacting with a driven nonlinear resonator

Suguru Endo, Yuichiro Matsuzaki, Kosuke Kakuyanagi +3

In the ultra-strong coupling regime of a light-matter system, the ground state exhibits non-trivial entanglement between the atom and photons. For the purposes of exploring the mea…

quant-ph2018

Hierarchy in temporal quantum correlations

Huan-Yu Ku, Shin-Liang Chen, Neill Lambert +2

Einstein-Podolsky-Rosen (EPR) steering is an intermediate quantum correlation that lies in between entanglement and Bell non-locality. Its temporal analogue, temporal steering, has…

cond-mat.mes-hall2024

Revealing non-Markovian Kondo transport with waiting time distributions

Feng-Jui Chan, Po-Chen Kuo, Neill Lambert +2

We investigate non-Markovian transport dynamics and signatures of the Kondo effect in a single impurity Anderson model. The model consists of a quantum dot (QD) with ultra-strong c…

quant-ph2018

Securing quantum networking tasks with multipartite Einstein-Podolsky-Rosen steering

Chien-Ying Huang, Neill Lambert, Che-Ming Li +2

Einstein-Podolsky-Rosen (EPR) steering is the explicit demonstration of the fact that the measurements of one party can in influence the quantum state held by another, distant, par…

quant-ph2021

Hidden nonmacrorealism: reviving the Leggett-Garg inequality with stochastic operations

Huan-Yu Ku, Hao-Cheng Weng, Yen-An Shih +5

The Leggett-Garg inequality (LGI) distinguishes nonmacrorealistic channels from macrorealistic ones by constraining the experimental outcomes of the underlying system. In this work…

cond-mat.mes-hall2015

Bistable Photon Emission from a Solid-State Single-Atom Laser

Neill Lambert, Franco Nori, Christian Flindt

We predict a bistability in the photon emission from a solid-state single-atom laser comprising a microwave cavity coupled to a voltage-biased double quantum dot. To demonstrate th…

quant-ph2017

Superradiance with local phase-breaking effects

Nathan Shammah, Neill Lambert, Franco Nori +1

We study the superradiant evolution of a set of two-level systems spontaneously radiating under the effect of phase-breaking mechanisms. We investigate the dynamics generated b…

quant-ph2015

Tunable multiphonon blockade in coupled nanomechanical resonators

Adam Miranowicz, Jiri Bajer, Neill Lambert +2

A single phonon in a nonlinear nanomechanical resonator (NAMR) can block the excitation of a second phonon [Phys. Rev. A 82, 032101 (2010)]. This intrinsically quantum effect is ca…

quant-ph2010

Quantum limit of photothermal cooling

Simone De Liberato, Neill Lambert, Franco Nori

We study the problem of cooling a mechanical oscillator using the photothermal (bolometric) force. Contrary to previous attempts to model this system, we take into account the nois…

quant-ph2014

Surface plasmons in a metal nanowire coupled to colloidal quantum dots: Scattering properties and quantum entanglement

Guang-Yin Chen, Neill Lambert, Chung-Hsien Chou +2

We investigate coherent single surface-plasmon transport in a metal nanowire strongly coupled to two colloidal quantum dots. Analytical expressions are obtained for the transmissio…

quant-ph2025

Resource efficient certification of system environment entanglement solely from reduced system dynamics

Jhen-Dong Lin, Pao-Wen Tu, Kuan-Yi Lee +4

Certifying nonclassical correlations typically requires access to all subsystems, presenting a major challenge in open quantum systems coupled to inaccessible environments. Recent…

quant-ph2010

Unified single-photon and single-electron counting statistics: from cavity-QED to electron transport

Neill Lambert, Yueh-Nan Chen, Franco Nori

A key ingredient of cavity quantum-electrodynamics (QED) is the coupling between the discrete energy levels of an atom and photons in a single-mode cavity. The addition of periodic…

q-bio.BM2013

Rerouting Excitation Transfer in the Fenna-Matthews-Olson Complex

Guang-Yin Chen, Neill Lambert, Che-Ming Li +2

We investigate, using the Hierarchy method, the entanglement and the excitation transfer efficiency of the Fenna-Matthews-Olson complex under two different local modifications: the…

quant-ph2022

Pulse-level noisy quantum circuits with QuTiP

Boxi Li, Shahnawaz Ahmed, Sidhant Saraogi +4

The study of the impact of noise on quantum circuits is especially relevant to guide the progress of Noisy Intermediate-Scale Quantum (NISQ) computing. In this paper, we address th…

cond-mat.mes-hall2013

Electrical current and coupled electron-nuclear spin dynamics in double quantum dots

G. Giavaras, Neill Lambert, Franco Nori

We examine electronic transport in a spin-blockaded double quantum dot. We show that by tuning the strength of the spin-orbit interaction the current flowing through the double dot…

quant-ph2023

Modeling the unphysical pseudomode model with physical ensembles: simulation, mitigation, and restructuring of non-Markovian quantum noise

Mauro Cirio, Si Luo, Pengfei Liang +2

The influence of a Gaussian environment on a quantum system can be described by effectively replacing the continuum with a discrete set of ancillary quantum and classical degrees o…

quant-ph2014

Entangled-state generation and Bell inequality violations in nanomechanical resonators

J. Robert Johansson, Neill Lambert, Imran Mahboob +2

We investigate theoretically the conditions under which a multi-mode nanomechanical resonator, operated as a purely mechanical parametric oscillator, can be driven into highly nonc…

cond-mat.mes-hall2012

Vibrationally-mediated molecular transistors

D. H. Santamore, Neill Lambert, Franco Nori

We investigate the steady-state electronic transport through a suspended dimer molecule coupled to leads. When strongly coupled to a vibrational mode, the electron transport is enh…

quant-ph2009

Quantum chaos and critical behavior on a chip

Neill Lambert, Yueh-nan Chen, Robert Johannsson +1

The Dicke model describes N qubits (or two-level atoms) homogenously coupled to a bosonic mode. Here we examine an open-system realization of the Dicke model, which contains critic…

cond-mat.mes-hall2020

Shortcuts to Adiabatic Pumping in Classical Stochastic Systems

Ken Funo, Neill Lambert, Franco Nori +1

Adiabatic pumping is characterized by a geometric contribution to the pumped charge, which can be non-zero even in the absence of a bias. However, as the driving speed is increased…

quant-ph2019

Speeding-up a quantum refrigerator via counter-diabatic driving

Ken Funo, Neill Lambert, Bayan Karimi +3

We study the application of a counter-diabatic driving (CD) technique to enhance the thermodynamic efficiency and power of a quantum Otto refrigerator based on a superconducting qu…

quant-ph2023

Observation of a superradiant phase transition with emergent cat states

Ri-Hua Zheng, Wen Ning, Ye-Hong Chen +15

Superradiant phase transitions (SPTs) are important for understanding light-matter interactions at the quantum level, and play a central role in criticality-enhanced quantum sensin…

cond-mat.mes-hall2020

Collectively induced exceptional points of quantum emitters coupled to nanoparticle surface plasmons

Po-Chen Kuo, Neill Lambert, Adam Miranowicz +4

Exceptional points, resulting from non-Hermitian degeneracies, have the potential to enhance the capabilities of quantum sensing. Thus, finding exceptional points in different quan…

quant-ph2015

When do weak-coupling approaches accurately capture the dynamics of complex quantum systems?

Amir Fruchtman, Neill Lambert, Erik M. Gauger

Understanding the dynamics of higher-dimensional quantum systems embedded in a complex environment remains a significant theoretical challenge. While several approaches yielding nu…

quant-ph2014

Environmental dynamics, correlations, and the emergence of noncanonical equilibrium states in open quantum systems

Jake Iles-Smith, Neill Lambert, Ahsan Nazir

Quantum systems are invariably open, evolving under surrounding influences rather than in isolation. Standard open quantum system methods eliminate all information on the environme…

quant-ph2024

Non-Hermitian Pseudomodes for Strongly Coupled Open Quantum Systems: Unravelings, Correlations and Thermodynamics

Paul Menczel, Ken Funo, Mauro Cirio +2

The pseudomode framework provides an exact description of the dynamics of an open quantum system coupled to a non-Markovian environment. Using this framework, the influence of the…

quant-ph2022

Space-time dual quantum Zeno effect: Interferometric engineering of open quantum system dynamics

Jhen-Dong Lin, Ching-Yu Huang, Neill Lambert +3

Superposition of trajectories, which modify quantum evolutions by superposing paths through interferometry, has been utilized to enhance various quantum communication tasks. Howeve…

quant-ph2023

Kondo QED: The Kondo effect and photon trapping in a two-impurity Anderson model ultra-strongly coupled to light

Po-Chen Kuo, Neill Lambert, Mauro Cirio +3

The Kondo effect is one of the most studied examples of strongly correlated quantum many-body physics. Another type of strongly correlated physics that has only recently been explo…

quant-ph2023

QuTiP-BoFiN: A bosonic and fermionic numerical hierarchical-equations-of-motion library with applications in light-harvesting, quantum control, and single-molecule electronics

Neill Lambert, Tarun Raheja, Simon Cross +5

The "hierarchical equations of motion" (HEOM) method is a powerful exact numerical approach to solve the dynamics and find the steady-state of a quantum system coupled to a non-Mar…

quant-ph2026

RC-HEOM Hybrid Method for Non-Perturbative Open System Dynamics

Po-Rong Lai, Jhen-Dong Lin, Yi-Te Huang +3

The Hierarchical equations of motion (HEOM) method is an important non-perturbative technique, allowing numerically exact treatment of open quantum systems with strong coupling and…

quant-ph2025

Purified pseudomode model for nonlinear system-bath interactions

Cheng Zhang, Neill Lambert, Xin-Qi Li +2

The theory of purified pseudomodes [arXiv:2412.04264 (2024)] was recently developed to provide a numerical tool for the analysis of the properties of a quantum system and the envir…

quant-ph2021

Quantum steering as a witness of quantum scrambling

Jhen-Dong Lin, Wei-Yu Lin, Huan-Yu Ku +3

Quantum information scrambling describes the delocalization of local information to global information in the form of entanglement throughout all possible degrees of freedom. A nat…

physics.chem-ph2018

Optimizing co-operative multi-environment dynamics in a dark-state-enhanced photosynthetic heat engine

Melina Wertnik, Alex Chin, Franco Nori +1

We analyze the role of coherent, non-perturbative system-bath interactions in a photosynthetic heat engine. Using the reaction-coordinate formalism to describe the vibrational phon…

cond-mat.mes-hall2013

Photon-mediated electron transport in hybrid circuit-QED

Neill Lambert, Christian Flindt, Franco Nori

We investigate photon-mediated transport processes in a hybrid circuit-QED structure consisting of two double quantum dots coupled to a common microwave cavity. Under suitable reso…

quant-ph2008

Detecting quantum-coherent nanomechanical oscillations using the current-noise spectrum of a double quantum dot

Neill Lambert, Franco Nori

We consider a nanomechanical resonator coupled to a double quantum dot. We demonstrate how the finite-frequency current noise spectrum through the double quantum dot can be used to…

quant-ph2019

Virtual excitations in the ultra-strongly-coupled spin-boson model: physical results from unphysical modes

Neill Lambert, Shahnawaz Ahmed, Mauro Cirio +1

Here we show how, in the ultra-strongly-coupled spin-boson model, apparently unphysical "Matsubara modes" are required not only to regulate detailed balance, but also to arrive at…

quant-ph2014

A temporal steering inequality

Yueh-Nan Chen, Che-Ming Li, Neill Lambert +4

Quantum steering is the ability to remotely prepare different quantum states by using entangled pairs as a resource. Very recently, the concept of steering has been quantified with…

quant-ph2015

Ground State Electroluminescence

Mauro Cirio, Simone De Liberato, Neill Lambert +1

Electroluminescence, the emission of light in the presence of an electric current, provides information on the allowed electronic transitions of a given system. It is commonly used…

physics.bio-ph2012

Functional quantum biology in photosynthesis and magnetoreception

Neill Lambert, Yueh-Nan Chen, Yuan-Chung Cheng +3

Is there a functional role for quantum mechanics or coherent quantum effects in biological processes? While this question is as old as quantum theory, only recently have measuremen…

quant-ph2015

Certifying single-system steering for quantum information processing

Che-Ming Li, Yueh-Nan Chen, Neill Lambert +2

Einstein-Podolsky-Rosen (EPR) steering describes how different ensembles of quantum states can be remotely prepared by measuring one particle of an entangled pair. Here, we investi…

quant-ph2012

Witnessing Quantum Coherence: from solid-state to biological systems

Che-Ming Li, Neill Lambert, Yueh-Nan Chen +2

Quantum coherence is one of the primary non-classical features of quantum systems. While protocols such as the Leggett-Garg inequality (LGI) and quantum tomography can be used to t…

quant-ph2024

A purified input-output pseudomode model for structured open quantum systems

Pengfei Liang, Neill Lambert, Si Luo +2

A full understanding of open quantum systems requires the characterization of both system and environmental properties. However, the complexity of the environmental statistics in t…

quant-ph2015

Using non-Markovian measures to evaluate quantum master equations for photosynthesis

Hong-Bin Chen, Neill Lambert, Yuan-Chung Cheng +2

When dealing with system-reservoir interactions in an open quantum system, such as a photosynthetic light-harvesting complex, approximations are usually made to obtain the dynamics…

quant-ph2005

Entanglement in quantum catastrophes

Clive Emary, Neill Lambert, Tobias Brandes

We classify entanglement singularities for various two-mode bosonic systems in terms of catastrophe theory. Employing an abstract phase-space representation, we obtain exact result…

quant-ph2012

Delocalized single-photon Dicke states and the Leggett- Garg inequality in solid state systems

Guang-Yin Chen, Neill Lambert, Che-Ming Li +2

We show how to realize a single-photon Dicke state in a large one-dimensional array of two- level systems, and discuss how to test its quantum properties. Realization of single-pho…

quant-ph2020

Exact and efficient quantum simulation of open quantum dynamics for various of Hamiltonians and spectral densities

Na-Na Zhang, Ming-Jie Tao, Wan-Ting He +6

Recently, we have theoretically proposed and experimentally demonstrated an exact and efficient quantum simulation of photosynthetic light harvesting in nuclear magnetic resonance…

quant-ph2016

Amplified opto-mechanical transduction of virtual radiation pressure

Mauro Cirio, Kamanasish Debnath, Neill Lambert +1

Here we describe how, utilizing a time-dependent opto-mechanical interaction, a mechanical probe can provide an amplified measurement of the virtual photons dressing the quantum gr…

quant-ph2017

Plasmonic bio-sensing for the Fenna-Matthews-Olson complex

Guang-Yin Chen, Neill Lambert, Yen-An Shih +3

We study theoretically the bio-sensing capabilities of metal nanowire surface plasmons. As a specific example, we couple the nanowire to specific sites (bacteriochlorophyll) of the…

quant-ph2015

Increasing relative nonclassicality quantified by standard entanglement potentials by dissipation and unbalanced beam splitting

Adam Miranowicz, Karol Bartkiewicz, Neill Lambert +2

If a single-mode nonclassical light is combined with the vacuum on a beam splitter, then the output state is entangled. As proposed in [Phys. Rev. Lett. 94, 173602 (2005)], by meas…

quant-ph2024

Fixing detailed balance in ancilla-based dissipative state engineering

Neill Lambert, Mauro Cirio, Jhen-dong Lin +3

Dissipative state engineering is a general term for a protocol which prepares the ground state of a complex many-body Hamiltonian using engineered dissipation or engineered environ…

quant-ph2019

Multielectron Ground State Electroluminescence

Mauro Cirio, Nathan Shammah, Neill Lambert +2

The ground state of a cavity-electron system in the ultrastrong coupling regime is characterized by the presence of virtual photons. If an electric current flows through this syste…

quant-ph2024

Sudden change of the photon output field marks phase transitions in the quantum Rabi model

Ye-Hong Chen, Yuan Qiu, Adam Miranowicz +6

The experimental observation of quantum phase transitions predicted by the quantum Rabi model in quantum critical systems is usually challenging due to the lack of signature experi…

quant-ph2017

Amplified and tunable transverse and longitudinal spin-photon coupling in hybrid circuit-QED

Neill Lambert, Mauro Cirio, Matthieu Delbecq +4

We describe a method to tune, in-situ, between transverse and longitudinal light-matter coupling in a hybrid circuit-QED device composed of an electron spin degree of freedom coupl…

quant-ph2016

Nonequilibrium thermodynamics in the strong coupling and non-Markovian regime based on a reaction coordinate mapping

Philipp Strasberg, Gernot Schaller, Neill Lambert +1

We propose a method to study the thermodynamic behaviour of small systems beyond the weak coupling and Markovian approximation, which is different in spirit from conventional appro…

quant-ph2024

Non-Markovian skin effect

Po-Chen Kuo, Shen-Liang Yang, Neill Lambert +4

The Liouvillian skin effect and the non-Hermitian skin effect have both been used to explain the localization of eigenmodes near system boundaries, though the former is arguably mo…

quant-ph2012

Confidence and Backaction in the Quantum Filter Equation

Wei Cui, Neill Lambert, Yukihiro Ota +4

We study the confidence and backaction of state reconstruction based on a continuous weak measurement and the quantum filter equation. As a physical example we use the traditional…

quant-ph2014

Leggett-Garg Inequalities

Clive Emary, Neill Lambert, Franco Nori

In contrast to the spatial Bell's inequalities, which probe entanglement between spatially-separated systems, the Leggett-Garg inequalities test the correlations of a single system…

quant-ph2011

A macro-realism inequality for opto-electro-mechanical systems

Neill Lambert, Robert Johansson, Franco Nori

We show how to apply the Leggett-Garg inequality to opto-electro-mechanical systems near their quantum ground state. We find that by using a dichotomic quantum non-demolition measu…

quant-ph2021

Nonequilibrium heat transport and work with a single artificial atom coupled to a waveguide: emission without external driving

Yong Lu, Neill Lambert, Anton Frisk Kockum +5

We observe the continuous emission of photons into a waveguide from a superconducting qubit without the application of an external drive. To explain this observation, we build a tw…

physics.chem-ph2020

Beyond Marcus theory and the Landauer-Buttiker approach in molecular junctions. II. A self-consistent Born approach

Jakub K. Sowa, Neill Lambert, Tamar Seideman +1

Marcus and Landauer-Buttiker approaches to charge transport through molecular junctions describe two contrasting mechanisms of electronic conduction. In previous work, we have show…

quant-ph2016

Leggett--Garg inequality violations with a large ensemble of qubits

Neill Lambert, Kamanasish Debnath, Anton Frisk Kockum +3

We investigate how discrete internal degrees of freedom in a quasi-macroscopic system affect the violation of the Leggett--Garg inequality, a test of macroscopic-realism based on t…

quant-ph2021

Unveiling and veiling a Schrödinger cat state from the vacuum

Roberto Stassi, Mauro Cirio, Ken Funo +3

Deep in the ultrastrong light-matter coupling regime, it has been predicted that the ground state of a two-level atom interacting with a cavity mode takes the form of a "virtual" S…

cond-mat.mes-hall2024

Lee-Yang theory of the superradiant phase transition in the open Dicke model

Fredrik Brange, Neill Lambert, Franco Nori +1

The Dicke model describes an ensemble of two-level atoms that are coupled to a confined light mode of an optical cavity. Above a critical coupling, the cavity becomes macroscopical…

quant-ph2021

The Fermionic influence superoperator: a canonical derivation for the development of methods to simulate the influence of a Fermionic environment on a quantum system with arbitrary parity symmetry

Mauro Cirio, Po-Chen Kuo, Yueh-Nan Chen +2

We present a canonical derivation of an influence superoperator which generates the reduced dynamics of a Fermionic quantum system linearly coupled to a Fermionic environment initi…

quant-ph2009

Detecting non-Markovian plasmonic band gaps in quantum dots using electron transport

Yueh-Nan Chen, Guang-Yin Chen, Ying-Yen Liao +2

Placing a quantum dot close to a metal nanowire leads to drastic changes in its radiative decay behavior because of evanescent couplings to surface plasmons. We show how two non-Ma…

quant-ph2020

Experimental test of non-macrorealistic cat-states in the cloud

Huan-Yu Ku, Neill Lambert, Fong-Ruei Jhan +3

The Leggett-Garg inequality attempts to classify experimental outcomes as arising from one of two possible classes of physical theories: those described by macrorealism (which obey…

quant-ph2025

QuTiP 5: The Quantum Toolbox in Python

Neill Lambert, Eric Giguère, Paul Menczel +15

QuTiP, the Quantum Toolbox in Python, has been at the forefront of open-source quantum software for the past 13 years. It is used as a research, teaching, and industrial tool, and…

quant-ph2003

Entanglement and the Phase Transition in Single Mode Superradiance

Neill Lambert, Clive Emary, Tobias Brandes

We consider the entanglement properties of the quantum phase transition in the single-mode superradiance model, involving the interaction of a boson mode and an ensemble of atoms.…

quant-ph2016

Spatio-Temporal Steering for Testing Nonclassical Correlations in Quantum Networks

Shin-Liang Chen, Neill Lambert, Che-Ming Li +4

We introduce the concept of spatio-temporal steering (STS), which reduces, in special cases, to Einstein-Podolsky-Rosen steering and the recently-introduced temporal steering. We d…

quant-ph2024

Non-Markovian Quantum Exceptional Points

Jhen-Dong Lin, Po-Chen Kuo, Neill Lambert +3

Exceptional points (EPs) are singularities in the spectra of non-Hermitian operators, where eigenvalues and eigenvectors coalesce. Recently, open quantum systems have been increasi…

quant-ph2025

Input-Output Hierarchical Equations Of Motion

Mauro Cirio, Pengfei Liang, Neill Lambert

We derive an extended version of the hierarchical equations of motion (HEOM) to compute output physical properties of a bosonic environment, which is allowed to be initially prepar…