Publications (33)
Ab Initio Molecular Dynamics on the Electronic Boltzmann Equilibrium Distribution
J. L. Alonso, A. Castro, P. Echenique +3
We prove that for a combined system of classical and quantum particles, it is possible to write a dynamics for the classical particles that incorporates in a natural way the Boltzm…
Blueprint of a Molecular Spin Quantum Processor
A. Chiesa, S. Roca, S. Chicco +6
The implementation of a universal quantum processor still poses fundamental issues related to error mitigation and correction, which demand to investigate also platforms and comput…
Non-equilibrium Effects in the Thermal Switching of Underdamped Josephson Junctions
J. J. Mazo, F. Naranjo, D. Zueco
We study the thermal escape problem in the low damping limit. We find that finiteness of the barrier is crucial for explaining the thermal activation results. In this regime low ba…
Thermal activation at moderate-to-high and high damping: finite barrier effects and force spectroscopy
J. J. Mazo, O. Y. Fajardo, D. Zueco
We study the thermal escape problem in the moderate-to-high and high damping regime of a system with a parabolic barrier. We present a formula that matches our numerical results ac…
Solving spin quantum-master equations with matrix continued-fraction methods: application to superparamagnets
J. L. Garcia-Palacios, D. Zueco
We implement continued-fraction techniques to solve exactly quantum master equations for a spin with arbitrary S coupled to a (bosonic) thermal bath. The full spin density matrix i…
High cooperativity coupling to nuclear spins on a circuit QED architecture
V. Rollano, M. C. de Ory, C. D. Buch +9
Nuclear spins are candidates to encode qubits or qudits due to their isolation from magnetic noise and potentially long coherence times. However, their weak coupling to external st…
From Josephson junction metamaterials to tunable pseudo-cavities
D. Zueco, C. Fernández-Juez, J. Yago +4
The scattering through a Josephson junction interrupting a superconducting line is revisited including power leakage. We discuss also how to make tunable and broadband resonant mir…
Nonequilibrium and nonperturbative dynamics of ultrastrong coupling in open lines
B. Peropadre, D. Zueco, D. Porras +1
We study the time and space resolved dynamics of a qubit with an Ohmic coupling to propagating 1D photons, from weak coupling to the ultrastrong coupling regime. A nonperturbative…
Ultrastrong coupling in two-resonator circuit QED
A. Baust, E. Hoffmann, M. Haeberlein +17
We report on ultrastrong coupling between a superconducting flux qubit and a resonant mode of a system comprised of two superconducting coplanar stripline resonators coupled galvan…
Creation and manipulation of entanglement in spin chains far from equilibrium
F. Galve, D. Zueco, G. M. Reuther +2
We investigate creation, manipulation, and steering of entanglement in spin chains from the viewpoint of quantum communication between distant parties. We demonstrate how global pa…
A scalable architecture for quantum computation with molecular nanomagnets
M. D. Jenkins, D. Zueco, O. Roubeau +3
A proposal for a magnetic quantum processor that consists of individual molecular spins coupled to superconducting coplanar resonators and transmission lines is carefully examined.…
Non-adiabatic effects within a single thermally-averaged potential energy surface: Thermal expansion and reaction rates of small molecules
J. L. Alonso, A. Castro, J. Clemente-Gallardo +5
At non-zero temperature and when a system has low-lying excited electronic states, the ground-state Born--Oppenheimer approximation breaks down and the low-lying electronic states…
Longitudinal relaxation and thermoactivation of quantum superparamagnets
D. Zueco, J. l. Garcia-Palacios
The relaxation mechanisms of a quantum nanomagnet are discussed in the frame of linear response theory. We use a spin Hamiltonian with a uniaxial potential barrier plus a Zeeman te…
Strong spin-magnon coupling in a van der Waals magnet with tunable chiral symmetry
D. GarcÃa-Pons, J. Pérez-Bailón, C. Boix-Constant +6
Quantum technologies require platforms that can coherently interface qubits with bosonic excitations. Photons have traditionally played this role in cavity quantum electrodynamics,…
Electromagnetic wave transmission through a small hole in a perfect electric conductor of finite thickness
A. Yu. Nikitin, D. Zueco, F. J. Garcia-Vidal +1
The non-resonant electromagnetic transmission of a normal-incident plane wave through a single hole in a perfect conductor metal slab of finite width is studied. The cases of recta…
Dynamical signatures of bound states in waveguide QED
E. Sánchez-Burillo, D. Zueco, L. MartÃn-Moreno +1
We study the spontaneous decay of an impurity coupled to a linear array of bosonic cavities forming a single-band photonic waveguide. The average frequency of the emitted photon is…
Mode-Locking of mobile discrete breathers
D. Zueco, P. J. Martinez, L. M. Floria +1
We study numerically synchronization phenomena of mobile discrete breathers in dissipative nonlinear lattices periodically forced. When varying the driving intensity, the breather…
Fast microwave beam splitters from superconducting resonators
M. Haeberlein, D. Zueco, P. Assum +8
Coupled superconducting transmission line resonators have applications in quantum information processing and fundamental quantum mechanics. A particular example is the realization…
Tunable coupling engineering between superconducting resonators: from sidebands to effective gauge fields
B. Peropadre, D. Zueco, F. Wulschner +4
In this work we show that a tunable coupling between microwave resonators can be engineered by means of simple Josephson junctions circuits, such as dc- and rf-SQUIDs. We show that…
Molecular prototypes for spin-based CNOT quantum gates
F. Luis, A. Repollés, M. J. MartÃnez-Pérez +8
We show that a chemically engineered structural asymmetry in [Tb2] molecular clusters renders the two weakly coupled Tb3+ spin qubits magnetically inequivalent. The magnetic energy…
Non-linear response of single-molecule magnets: field-tuned quantum-to-classical crossovers
R. Lopez-Ruiz, F. Luis, A. Millan +3
Quantum nanomagnets can show a field dependence of the relaxation time very different from their classical counterparts, due to resonant tunneling via excited states (near the anis…
Beyond the Jaynes-Cummings model: circuit QED in the ultrastrong coupling regime
T. Niemczyk, F. Deppe, H. Huebl +9
In cavity quantum electrodynamics (QED), light-matter interaction is probed at its most fundamental level, where individual atoms are coupled to single photons stored in three-dime…
Bopp operators and phase-space spin dynamics: Application to rotational quantum brownian motion
D. Zueco, Ivan Calvo
As already known for nonrelativistic spinless particles, Bopp operators give an elegant and simple way to compute the dynamics of quasiprobability distributions in the phase space…
Tunable and Switchable Coupling Between Two Superconducting Resonators
A. Baust, E. Hoffmann, M. Haeberlein +16
We realize a device allowing for tunable and switchable coupling between two superconducting resonators mediated by an artificial atom. For the latter, we utilize a persistent curr…
Coupling single molecule magnets to quantum circuits
M. D. Jenkins, T. Hümmer, M. J. MartÃnez-Pérez +3
In this work we study theoretically the coupling of single molecule magnets (SMMs) to a variety of quantum circuits, including microwave resonators with and without constrictions a…
Enhanced molecular spin-photon coupling at superconducting nanoconstrictions
I. Gimeno, W. Kersten, M. C. Pallarés +9
We combine top-down and bottom-up nanolithography to optimize the coupling of small molecular spin ensembles to GHz on-chip superconducting resonators. Nanoscopic constrictio…
Quantum Ratchets at High Temperatures
D. Zueco, J. L. Garcia-Palacios
Using the continued-fraction method we solve the Caldeira-Leggett master equation in the phase-space (Wigner) representation to study Quantum ratchets. Broken spatial symmetry, irr…
Caldeira--Leggett quantum master equation in Wigner phase space: continued-fraction solution and application to Brownian motion in periodic potentials
J. L. Garcia-Palacios, D. Zueco
The continued-fraction method to solve classical Fokker--Planck equations has been adapted to tackle quantum master equations of the Caldeira--Leggett type. This can be done taking…
Weak and Strong coupling regimes in plasmonic-QED
T. Hümmer, F. J. GarcÃa-Vidal, L. MartÃn-Moreno +1
We present a quantum theory for the interaction of a two level emitter with surface plasmon polaritons confined in single-mode waveguide resonators. Based on the Green's function a…
A perspective on scaling up quantum computation with molecular spins
S. Carretta, D. Zueco, A. Chiesa +2
Artificial magnetic molecules can contribute to progressing towards large scale quantum computation by: a) integrating multiple quantum resources and b) reducing the computational…
Non-reciprocal population dynamics in a quantum trimer
C. A. Downing, D. Zueco
We study a quantum trimer of coupled two-level systems beyond the single-excitation sector, where the coherent coupling constants are ornamented by a complex phase. Accounting for…
Broad-band spectroscopy of a vanadyl porphyrin: a model electronuclear spin qudit
I. Gimeno, A. Urtizberea, J. Román-Roche +5
We explore how to encode more than a qubit in vanadyl porphyrin molecules hosting a electronic spin 1/2 coupled to a nuclear spin 7/2. The spin Hamiltonian and its parameters, as w…
Full two-photon downconversion of just a single photon
E. Sánchez-Burillo, L. MartÃn-Moreno, J. J. GarcÃa-Ripoll +1
We demonstrate, both numerically and analytically, that it is possible to generate two photons from one and only one photon. We characterize the output two photon field and make ou…