Publications (2022)
Exponential time-scaling of estimation precision by reaching a quantum critical point
Authors: Garbe, Louis; Abah, Obinna; Felicetti, Simone; Puebla, Ricardo
Journal: PHYSICAL REVIEW RESEARCH
Publication date: 2022/10/26
DOI: 10.1103/PhysRevResearch.4.043061
Abstract: Quantum metrology refers to the use of quantum resources in parameter-estimation protocols, aiming at enhancing its precision. The quantum Fisher information is a key quantity in this context, setting the ultimate achievable precision with respect to available resources, such as the total time of the protocol. In this work, we report a scheme where the quantum Fisher information features an exponential scaling with the protocol duration. This is achieved by performing a […]
Locality of spontaneous symmetry breaking and universal spacing distribution of topological defects formed across a phase transition
Authors: del Campo, Adolfo; Javier Gomez-Ruiz, Fernando; Zhang, Hai-Qing
Journal: PHYSICAL REVIEW B
Publication date: 2022/10/11
DOI: 10.1103/PhysRevB.106.L140101
Abstract: The crossing of a continuous phase transition results in the formation of topological defects with a density predicted by the Kibble-Zurek mechanism (KZM). We characterize the spatial distribution of pointlike topological defects in the resulting nonequilibrium state and model it using a Poisson point process in arbitrary spatial dimensions with KZM density. Numerical simulations in a one-dimensional phi 4 theory unveil short-distance defect-defect corrections stemming from the kink excluded volume, while in […]
Role of boundary conditions in the full counting statistics of topological defects after crossing a continuous phase transition
Authors: Gomez-Ruiz, Fernando J.; Subires, David; del Campo, Adolfo
Journal: PHYSICAL REVIEW B
Publication date: 2022/10/10
DOI: 10.1103/PhysRevB.106.134302
Abstract: In a scenario of spontaneous symmetry breaking in finite time, topological defects are generated at a density that scales with the driving time according to the Kibble-Zurek mechanism (KZM). Signatures of universality beyond the KZM have recently been unveiled: The number distribution of topological defects has been shown to follow a binomial distribution, in which all cumulants inherit the universal power-law scaling with the quench rate, with cumulant rations being constant. In […]
The role of high-energy phonons in electron-phonon interaction at conducting surfaces with helium-atom scattering
Authors: Benedek, G.; Manson, J. R.; Miret-Artes, Salvador
Journal: PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Publication date: 2022/10/05
DOI: 10.1039/d2cp03501d
Abstract: In previous works it has been shown that the Debye-Waller (DW) exponent for Helium atom specular reflection from a conducting surface, when measured as a function of temperature in the linear high-temperature regime, allows for the determination of the surface electron-phonon coupling. However, there exist a number of experimental measurements that exhibit non-linearities in the DW exponent as a function of the surface temperature. Such non-linearities have been suggested as due to […]
Dynamical photon-photon interaction mediated by a quantum emitter
Authors: Le Jeannic, Hanna; Tiranov, Alexey; Carolan, Jacques; Ramos, Tomas; Wang, Ying; Appel, Martin Hayhurst; Scholz, Sven; Wieck, Andreas D.; Ludwig, Arne; Rotenberg, Nir; Midolo, Leonardo; Garcia-Ripoll, Juan Jose; Sorensen, Anders S.; Lodahl, Peter
Journal: NATURE PHYSICS
Publication date: 2022/10/01
DOI: 10.1038/s41567-022-01720-x
Abstract: Single photons role in the development of quantum science and technology. They can carry quantum information over extended distances to act as the backbone of a future quantum Internet(1) and can be manipulated in advanced photonic circuits, enabling scalable photonic quantum computing(2,3). However, more sophisticated devices and protocols […]
Importance of radiative pumping for the excitation of the H2O submillimeter lines in galaxies
Authors: Gonzalez-Alfonso, Eduardo; Fischer, Jacqueline; Goicoechea, Javier R.; Yang, Chentao; Pereira-Santaella, Miguel; Stewart, Kenneth P.
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2022/09/29
DOI: 10.1051/0004-6361/202244700
Abstract: H2O submillimeter emission is a powerful diagnostic of the molecular interstellar medium in a variety of sources, including low- and high-mass star-forming regions of the Milky Way, and from local to high-redshift galaxies. However, the excitation mechanism of these lines in galaxies has been debated, preventing a basic consensus on the physical information that H2O provides. Radiative pumping due to H2O absorption of far-infrared photons emitted […]
Dissecting the central regions of OH 231.8+4.2 with ALMA: A salty rotating disk at the base of a young bipolar outflow
Authors: Contreras, C. Sanchez; Alcolea, J.; Cardoso, R. Rodriguez; Bujarrabal, V; Castro-Carrizo, A.; Quintana-Lacaci, G.; Velilla-Prieto, L.; Santander-Garcia, M.
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2022/09/14
DOI: 10.1051/0004-6361/202243623
Abstract: We present a set of Atacama Large Millimeter/submillimeter Array (ALMA) continuum and molecular line emission maps at 1 mm wavelengths of OH 231.8+4.2. This is a well studied bipolar nebula around an asymptotic giant branch (AGB) star that is key in investigations of the origin of the remarkable changes in nebular morphology and kinematics during the short transition from the AGB to […]
Modeling of Structure H Carbon Dioxide Clathrate Hydrates: Guest-Lattice Energies, Crystal Structure, and Pressure Dependencies
Authors: Cabrera-Ramirez, Adriana; Prosmiti, Rita
Journal: JOURNAL OF PHYSICAL CHEMISTRY C
Publication date: 2022/09/08
Abstract: We performed first-principles computations to investigate the complex interplay of molecular interaction energies in determining the lattice structure and stability of CO2@sH clathrate hydrates. Density functional theory computations using periodic boundary conditions were employed to characterize energetics and the key structural properties of the sH clathrate crystal under pressure, such as equilibrium lattice volume and bulk modulus. The performance of exchange-correlation functionals together with recently developed dispersion-corrected schemes was evaluated in describing interactions in […]
Multilayer Graphtriyne Membranes for Separation and Storage of CO2: Molecular Dynamics Simulations of Post-Combustion Model Mixtures
Authors: Apriliyanto, Yusuf Bramastya; Faginas-Lago, Noelia; Evangelisti, Stefano; Bartolomei, Massimiliano; Leininger, Thierry; Pirani, Fernando; Pacifici, Leonardo; Lombardi, Andrea
Journal: MOLECULES
Publication date: 2022/09/01
DOI: 10.3390/molecules27185958
Abstract: The ability to remove carbon dioxide from gaseous mixtures is a necessary step toward the reduction of greenhouse gas emissions. As a contribution to this field of research, we performed a molecular dynamics study assessing the separation and adsorption properties of multi-layered graphtriyne membranes on gaseous mixtures of CO2, N-2, and H2O. These mixtures closely resemble post-combustion gaseous products and are, therefore, suitable prototypes with […]
Electron and Positron Scattering Cross Sections from CO2: A Comparative Study over a Broad Energy Range (0.1-5000 eV)
Authors: Lozano, Ana, I; Garcia-Abenza, Adrian; Blanco Ramos, Francisco; Hasan, Mahmudul; Slaughter, Daniel S.; Weber, Thorsten; McEachran, Robert P.; White, Ronald D.; Brunger, Michael J.; Limao-Vieira, Paulo; Gomez-Tejedor, Gustavo Garcia
Journal: JOURNAL OF PHYSICAL CHEMISTRY A
Publication date: 2022/09/01
Abstract: In this Review, we present a comparative study between electron and positron scattering cross sections from CO2 molecules over a broad impact energy range (0.1-5000 eV). For electron scattering, new total electron scattering cross sections (e-TCS) have been measured with a high resolution magnetically confined electron beam transmission system […]
QUANTUM COMPUTING Optimal simulation of quantum dynamics
Authors: Tagliacozzo, Luca
Journal: NATURE PHYSICS
Publication date: 2022/09/01
DOI: 10.1038/s41567-022-01696-8
Abstract: Tensor networks are mathematical structures that efficiently compress the data required to describe quantum systems. An algorithm for the optimal simulation of quantum dynamics based on tensor networks has now been implemented on a trapped-ion processor.
The role of highly vibrationally excited H-2 initiating the nitrogen chemistry Quantum study and 3 sigma – detection of NH emission in the Orion Bar PDR
Authors: Goicoechea, Javier R.; Roncero, Octavio
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2022/08/31
DOI: 10.1051/0004-6361/202243884
Abstract: The formation of hydrides by gas-phase reactions between H-2 and a heavy element atom is a very selective process. Reactions with ground-state neutral carbon, oxygen, nitrogen, and sulfur atoms are very endoergic and have high energy barriers because the H-2 molecule has to be fragmented before a hydride bond is formed. In cold interstellar clouds, these barriers exclude the formation of CH, OH, NH, and SH radicals through hydrogen abstraction reactions. Here we study a […]
Spin-orbit transitions in the N+(P-3 (JA))+H2 -> NH+(X-2 Pi, (4)Sigma(-)) + H(S-2) reaction, using adiabatic and mixed quantum-adiabatic statistical approaches
Authors: Gomez-Carrasco, Susana; Felix-Gonzalez, Daniel; Aguado, Alfredo; Roncero, Octavio
Journal: JOURNAL OF CHEMICAL PHYSICS
Publication date: 2022/08/28
DOI: 10.1063/5.0102376
Abstract: The cross section and rate constants for the title reaction are calculated for all the spin-orbit states of N+(P-3 (JA))using two statistical approaches, one purely adiabatic and the other one mixing quantum capture for the entrance channel and adiabatic treatment for the products channel. This is made by using a symmetry adapted basis set combining electronic (spin and orbital) and nuclear angular momenta in the reactants channel. To this aim, accurate […]
Extremely high spectral resolution measurements of the 450 mu m atmospheric window at Chajnantor with APEX
Authors: Pardo, J. R.; De Breuck, C.; Muders, D.; Gonzalez, J.; Montenegro-Montes, F. M.; Perez-Beaupuits, J. P.; Cernicharo, J.; Prigent, C.; Serabyn, E.; Mroczkowski, T.; Phillips, N.
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2022/08/24
DOI: 10.1051/0004-6361/202243409
Abstract: Ground-based telescopes observing at millimeter (mm) and submillimeter (submm) wavelengths have to deal with a line-rich and highly variable atmospheric spectrum, both in space and time. Models of this spectrum play an important role in planning observations that are appropriate for the weather conditions and also calibrating those observations. Through magnetic dipolar (M1) rotational […]
Variational Determination of Multiqubit Geometrical Entanglement in Noisy Intermediate-Scale Quantum Computers
Authors: Munoz-Moller, A. D.; Pereira, L.; Zambrano, L.; Cortes-Vega, J.; Delgado, A.
Journal: PHYSICAL REVIEW APPLIED
Publication date: 2022/08/17
DOI: 10.1103/PhysRevApplied.18.024048
Abstract: Current noise levels in physical realizations of qubits and quantum operations limit the applicability of conventional methods to characterize entanglement. In this adverse scenario, we follow a quantum variational approach to estimate the geometric measure of entanglement of multiqubit pure states. The algorithm requires only single-qubit gates and measurements, so it is well suited for noisy intermediate-scale quantum devices. This is demonstrated by successfully implementing the method on IBM […]