Article
Physics, Multidisciplinary
Daniel C. Cole, Stephen D. Erickson, Giorgio Zarantonello, Karl P. Horn, Pan-Yu Hou, Jenny J. Wu, Daniel H. Slichter, Florentin Reiter, Christiane P. Koch, Dietrich Leibfried
Summary: We demonstrate a simplified method for dissipative generation of an entangled state of two trapped-ion qubits, achieving a fidelity of 0.949 in approximately 7 ms. The dominant source of infidelity is photon scattering, and strategies for its mitigation are discussed.
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Ashis Chhetri, Kannimuthu Karthick, Arun Karmakar, Subrata Kundu, Joyee Mitra
Summary: Small organic molecules and hydrogen-bonded aggregates are being explored as alternatives to traditional electrocatalysts for the low-cost generation of H-2. The use of melamine and adipic acid-based hydrogen-bonded organic ionic systems as electrocatalysts for water oxidation reaction (WOR) has shown promising results, with high current density and efficiency. These systems offer modifiability and unique molecular composition, making them potential candidates for WOR electrocatalysis.
Article
Chemistry, Physical
Joel I-J Wang, Megan A. Yamoah, Qing Li, Amir H. Karamlou, Thao Dinh, Bharath Kannan, Jochen Braumuller, David Kim, Alexander J. Melville, Sarah E. Muschinske, Bethany M. Niedzielski, Kyle Serniak, Youngkyu Sung, Roni Winik, Jonilyn L. Yoder, Mollie E. Schwartz, Kenji Watanabe, Takashi Taniguchi, Terry P. Orlando, Simon Gustavsson, Pablo Jarillo-Herrero, William D. Oliver
Summary: The dielectric loss of hexagonal boron nitride (hBN) thin films in the microwave regime was studied by measuring the quality factor of parallel-plate capacitors (PPCs) made of NbSe2-hBN-NbSe2 heterostructures integrated into superconducting circuits. The research findings showed that hBN can be a promising dielectric material for building high-coherence quantum circuits with substantially reduced footprint and reduced qubit cross-talk. The integration of hBN and NbSe2 parallel-plate capacitors with aluminium Josephson junctions can realize transmon qubits with coherence times reaching 25 µs.
Article
Chemistry, Multidisciplinary
Ashis Chhetri, Kannimuthu Karthick, Arun Karmakar, Subrata Kundu, Joyee Mitra
Summary: Applications of small organic molecules and hydrogen-bonded aggregates for low-cost hydrogen generation are gaining traction. Melamine and adipic acid-based hydrogen-bonded organic ionic (BMA) and co-crystal systems have been explored as electrocatalysts for water oxidation reaction (WOR). The BMA system, with its unique molecular composition and hydrogen-bonded motifs, exhibits enhanced electrocatalytic activity and achieves a high current density at a relatively low overpotential.
Article
Physics, Multidisciplinary
Benedetto Militello, Anna Napoli
Summary: The system of two qubits and a resonator, under the influence of various noise sources, reveals the potential for synchronized evolution of the qubits. A direct qubit-qubit interaction and dissipation processes involving the resonator are crucial factors, along with consideration of the detrimental impact of local dephasing of the qubits.
Article
Engineering, Multidisciplinary
S. Abdel-Khalek, E. M. Khalil, Hammad Alotaibi, S. M. Abo-Dahab, Emad E. Mahmoud, M. Higazy
Summary: This paper explores the relationship between quantum Fisher information and bipartite system entanglement, focusing on the correlation between the dynamics of qubit-qubit entanglement and quantum Fisher information. The study shows how photon multiplicity and squeeze parameter affect the dynamics of QFI and entanglement quantifier, particularly in cases of absence and presence of dissipation effect. The results demonstrate the correlation between entanglement quantifiers and QFI with respect to the appearance of collapse and revival phenomena of atomic inversion.
ALEXANDRIA ENGINEERING JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Xin-Xin Yang, Xiao-Yan Yang, Liang-Liang Guo, Lei Du, Peng Duan, Zhi-Long Jia, Hai-Ou Li, Guo-Ping Guo
Summary: One significant source of decoherence in superconducting circuits, known as two-level systems (TLSs), is found in amorphous oxide layers. These circuits can also be utilized as spectral and temporal TLS probes. Recent advancements in superconducting qubits allow for comprehensive investigations on the physics of TLSs. In this study, the tunable Xmon qubit decoherence time and resonance frequency were measured for over 3 days to study stochastic fluctuations. Analysis of time-domain Allan deviation and frequency-domain power spectral density indicates that two TLSs near resonance with the qubit are responsible for the fluctuations. The location of these two TLSs near the junctions was determined through extracted oscillation in T1 decay.
APPLIED SCIENCES-BASEL
(2023)
Article
Chemistry, Physical
Sambarta Chatterjee, Nancy Makri
Summary: In the study of the dynamics of a two-level system coupled to a dissipative harmonic bath, it is found that the symmetry of the initial condition affects the motion of the reduced density matrix elements, and the purity reaches its maximally mixed value during relaxation, followed by recovery and potential approach to unity under low-temperature, weakly dissipative conditions. Unusual, nonmonotonic population dynamics are observed when the two-level system is initially in its ground state under such conditions.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Chen Wang, Zhixin Zhou, Yu Ouyang, Jianbang Wang, Ehud Neumann, Rachel Nechushtai, Itamar Willner
Summary: Gated dissipative artificial photosynthetic systems were explored to model dynamically modulated environmental effects on the photosynthetic apparatus. The activation of transient electron transfer quenching and kinetically modulated photosynthesis of NADPH were achieved through the use of fuel strands and inhibitors in the photochemical modules.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Multidisciplinary Sciences
S. Salimian, M. K. Tavassoly, M. Ghasemi
Summary: In this paper, the generation of distributed entangled states of superconducting qubits is studied using an entanglement swapping protocol in three successive stages. The process involves preparing maximally entangled states, modulating the qubit frequency through external magnetic fields, converting qubits into entangled states through measurements, and obtaining the distributed entangled state of target qubits. The effects of thermal decoherence on the success probability, concurrence, and fidelity of the entangled states are evaluated. It is found that the entanglement and success probability gradually decrease over time due to thermal noise.
SCIENTIFIC REPORTS
(2023)
Article
Biochemistry & Molecular Biology
Amber R. Titus, Pedro P. Madeira, Luisa A. Ferreira, Vladimir Y. Chernyak, Vladimir N. Uversky, Boris Y. Zaslavsky
Summary: This work presents experimental evidence that mesoscopic changes occur before macroscopic phase separation in aqueous mixtures. Through dynamic light scattering and spectroscopic analysis, quantitative estimates of these changes are obtained and a model of phase separation is developed.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Optics
Run-Ying Yan, Zhi-Bo Feng
Summary: An efficient scheme is proposed for controllable and accelerated generation of entangled states between two superconducting qubits. The technique of invariant-based shortcuts to adiabaticity allows for the controllable creation of two types of entangled state within a composite qubit-photon-qubit system. Numerical simulations demonstrate the robustness of the operations against decoherence effects.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Xiang Lin, Bohan Kou, Jinlian Cao, Peimin Weng, Xiaosheng Yan, Zhao Li, Yun-Bao Jiang
Summary: The formation of orthogonal homochiral supramolecular helices is proposed as a method to achieve spontaneous resolution, and chiral resolution is successfully achieved through the introduction of acetylalanine as the building block and a halogen atom.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Multidisciplinary Sciences
Wei Wu, Ze-Zhou Zhang
Summary: The study shows that the decay rate of a two-level system interacting with a dissipative environment can be significantly suppressed by introducing an ancillary degree of freedom, offering an alternative way to combat decoherence and achieve controllable quantum dissipative dynamics.
SCIENTIFIC REPORTS
(2021)
Article
Optics
Sebastian Luciano Gallardo, Daniel Dominguez, Maria Jose Sanchez
Summary: An entangled-state generation protocol for a system of two qubits driven with an ac signal and coupled through a resonator is presented. The mechanism of entanglement generation is explained by the interplay between unitary Landau-Zener-St??ckelberg (LZS) transitions induced by the applied ac signal and dissipative processes dominated by photon loss. It is found that the steady state of the system can be finely tuned to approach a Bell state, which is immune to photon loss. The effective two-qubit Hamiltonians reproducing the resonance patterns associated with LZS transitions are derived.
Article
Materials Science, Multidisciplinary
Hazem Abu-Farsakh, Abdallah Qteish
Summary: The modified Becke-Johnson exchange potential combined with local-density approximation correlation shows highly improved band gaps with low computational cost. The study confirms that the number of valence electrons treated in pseudopotentials has a significant impact on the calculated band gaps. Including some outer core states as valence resolves this problem and improves the accuracy of the mBJLDA@PP approach for band gap calculations.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Physics, Condensed Matter
Rami Omari, Jamal Talla, Hazem Abu-Farsakh, Khaled Al-Khaza'leh
Summary: In this study, the effect of tensile stress on electronic properties in bulk pristine silicon carbide and Titanium-doped silicon carbide was investigated using first-principle calculations. The results showed a clear band gap closing in all structures, with symmetric behavior observed when titanium was in the silicon substitutional site and asymmetric behavior when in the carbon substitutional site. Additionally, systematic shifts in the Fermi energy were observed in response to applied stress and tensile strain.
COMPUTATIONAL CONDENSED MATTER
(2022)
Article
Chemistry, Physical
Intuon Chatratin, Baoying Dou, Su-Huai Wei, Anderson Janotti
Summary: Low p-type doping is a challenge for increasing the efficiency of CdTe thin-film solar cells. Previous calculations suggested high ionization energies for group-V acceptors, which resulted in self-compensation and limited hole concentration. However, recent experiments on CdTe single crystals showed that P, As, and Sb behave as shallow acceptors. Through hybrid functional calculations, it was found that the ionization energies decrease significantly with the supercell size. Including the effects of spin-orbit coupling and extrapolating to the dilute limit, it was determined that these impurities act as hydrogenic-like shallow acceptors, and AX centers do not limit p-type doping. Comparison with previous theoretical predictions and agreement with temperature-dependent Hall measurements were also discussed.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Physics, Applied
Su-Hyun Yoo, Mira Todorova, Jorg Neugebauer, Chris G. Van de Walle
Summary: GaN/(Al, Ga)N heterojunctions are crucial for high-electron-mobility transistors. The density of the two-dimensional electron gas (2DEG) on the GaN side is significantly enhanced by the strong polarization fields at the interface. The source of the electrons in the 2DEG is intrinsic to the overall structure and the negative charge is balanced by fixed charge on the surface, rather than surface states.
PHYSICAL REVIEW APPLIED
(2023)
Article
Chemistry, Multidisciplinary
Hazem Abu-Farsakh, Banat Gul, Muhammad Salman Khan
Summary: CdTe is investigated for its potential in efficient and stable solar cell production. The electronic, optical, and thermoelectric properties of different structural phases of CdTe were studied using density functional theory. The band structures varied among the phases, with some exhibiting direct band gaps and others showing indirect band gaps. The hybridization of Te-p and Cd-s bands was observed in the valence region. The dielectric function showed a slight decrease in the real component and an increase in the imaginary component with increasing photonic energy. The (5-phase exhibited higher reflectivity and showed potential for protecting against high energy radiations. The computed band gaps were inversely related to the refractive index, and the thermoelectric parameters indicated the potential use of these phases in thermoelectric devices.
Article
Quantum Science & Technology
Mehmet T. Uysal, Mouktik Raha, Songtao Chen, Christopher M. Phenicie, Salim Ourari, Mengen Wang, Chris G. Van de Walle, Viatcheslav V. Dobrovitski, Jeff D. Thompson
Summary: In this work, coherent coupling between the electron spin of a single Er3+ ion and a single I = 1/2 nuclear spin in the solid-state host crystal, which is a fortuitously located proton (1H), is demonstrated. The nuclear spin is controlled using dynamical-decoupling sequences applied to the electron spin, allowing for one- and two-qubit gate operations. The longer coherence time of the nuclear spin, compared to the electron spin, is crucial for combining long-lived nuclear spin quantum registers with telecom-wavelength emitters for long-distance quantum repeaters.
Article
Chemistry, Multidisciplinary
Dai Q. Ho, Ruiqi Hu, D. Quang To, Garnett W. Bryant, Anderson Janotti
Summary: Thin films of rare-earth monopnictide semimetals can turn into quantum spin Hall insulators when the thickness is reduced, due to the quantum confinement effects. This phenomenon, which is anticipated to be general in this family of materials, can lead to interesting effects when coupled with the 4f magnetic moments.
Article
Chemistry, Physical
Pir Muhammad Ismail, Sharafat Ali, Fazal Raziq, Mohamed Bououdina, Hazem Abu-Farsakh, Pengfei Xia, Xiaoqiang Wu, Haiyan Xiao, Sajjad Ali, Liang Qiao
Summary: In this study, WS2 nanosheets with S-vacancies were used as a support for single-atom catalysts such as Co, Cu, Ni, Pt, and Pd. The addition of S-vacancies and single metal atoms changed the electronic structure of WS2 and reduced its band gap value. The Cu- and Co/S-vacancy WS2 system showed good activity for the reduction of CO2 to formic acid and CO, making it an effective catalyst for CO2 activation and reduction.
APPLIED SURFACE SCIENCE
(2023)
Article
Physics, Multidisciplinary
Fangzhou Zhao, Mark E. Turiansky, Audrius Alkauskas, Chris G. Van de Walle
Summary: Trap-assisted Auger-Meitner recombination is highlighted as a dominant nonradiative process in wide-band-gap materials, and a first-principles methodology is presented to determine the rates of this process in semiconductors or insulators due to defects or impurities.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Physical
Intuon Chatratin, Baoying Dou, Su-Huai Wei, Anderson Janotti
Summary: Low p-type doping has been a barrier to achieving high efficiency in CdTe thin-film solar cells. Previous calculations predicted high ionization energies for group-V acceptors, leading to self-compensation and limited hole concentration. However, recent experiments on CdTe single crystals show that P, As, and Sb can behave as shallow acceptors. Using hybrid functional calculations, we demonstrate that the ionization energies decrease significantly with supercell size, and at the dilute limit, these impurities exhibit hydrogenic-like shallow acceptor behavior, eliminating the limitations of self-compensation.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Ymir K. Frodason, Joel B. Varley, Klaus Magnus H. Johansen, Lasse Vines, Chris G. Van de Walle
Summary: Pathways and energy barriers for the migration of Ga vacancies (VGa) and Ga interstitials (Gai) in-Ga2O3 have been studied using hybrid functional calculations and the nudged elastic band method. A mechanism for the transformation of VGa between different split configurations has been described. The overall migration barriers for VGa and Gai in different crystal directions have been determined. The results provide insights into the thermally activated recovery processes in irradiated material.
Article
Materials Science, Multidisciplinary
Mateus B. P. Querne, Jean M. Bracht, Juarez L. F. Da Silva, Anderson Janotti, Matheus P. Lima
Summary: Two-dimensional semiconductor materials have the potential for unconventional applications, and their properties are still being explored. In this study, the researchers used ab initio simulations to investigate a class of emerging 2D materials, and found that one structure has higher stability and different optoelectronic properties compared to another structure.
Article
Materials Science, Multidisciplinary
Yubi Chen, Mark E. Turiansky, Chris G. Van de Walle
Summary: This study conducted comprehensive investigations on native point defects in beryllium oxide (BeO) using density functional theory. The stability and potential applications of different defects were analyzed, and suitable candidates for quantum defects were identified.
Article
Quantum Science & Technology
Raj N. Patel, David A. Hopper, Jordan A. Gusdorff, Mark E. Turiansky, Tzu-Yung Huang, Rebecca E. K. Fishman, Benjamin Porat, Chris G. Van de Walle, Lee C. Bassett
Summary: By using photon emission correlation spectroscopy, we revealed the optical dynamics of quantum emitters in hexagonal boron nitride. The experimental results showed the existence of quantum emitters with ideal single-photon emission and their photoluminescence emission lineshapes were consistent with individual vibronic transitions. However, polarization-resolved excitation and emission revealed the role of multiple optical transitions, and photon emission correlation spectroscopy revealed the complicated optical dynamics associated with excitation and relaxation.
Article
Materials Science, Multidisciplinary
Muhammad Salman Khan, Banat Gul, Hazem Abu-Farsakh, Gulzar Khan
Summary: In this study, a comprehensive investigation was conducted on the structural, optoelectronic, and thermoelectric properties of novel ternary chalcogenides NaLiX (X = S, Se, Te). The electronic properties and band structure were calculated using the WC-GGA exchange correlation and the accurate TB-mBJ method within the density functional theory framework. The results indicate that these materials have wide bandgaps and strong covalent bonding, suggesting their potential applications in optoelectronic and thermoelectric devices.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)