Article
Multidisciplinary Sciences
Luke D. Smith, Jean Deviers, Daniel R. Kattnig
Summary: This study investigates the correlation between coherence measures and compass fidelity in large radical pair models. The results demonstrate the importance of global coherence measure in predicting compass sensitivity, while electronic coherence is found to be ineffective. These findings provide insights into the quantum nature of the avian compass.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Physical
Yiteng Zhang, Zixuan Hu, Yuchen Wang, Sabre Kais
Summary: Simulation of open quantum dynamics on quantum circuits has recently gained wide interest, with the development and demonstration of various quantum algorithms. Among them, a unitary dilation-based quantum algorithm has been designed to simulate general and complex physical systems. In this paper, we apply this quantum algorithm to simulate the dynamics of the radical pair mechanism in the avian compass. The simulation is conducted on the IBM QASM quantum simulator. This work represents the first application of any quantum algorithm to simulate the radical pair mechanism in the avian compass, demonstrating the generality of the quantum algorithm and opening up new opportunities for studying the avian compass with quantum computing devices.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Alec J. Coffman, Zuxin Jin, Junhan Chen, Joseph E. Subotnik, D. Vale Cofer-Shabica
Summary: We have developed a rare-event sampling scheme to quantify the rate of thermally activated nonadiabatic transitions in the condensed phase. Through surface hopping scheme, our simulations provide insight into the participation ratio of a solvent and the effect of ion separation distance on electron transfer.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Physics, Multidisciplinary
Hyukjoon Kwon, Rick Mukherjee, M. S. Kim
Summary: An important issue in developing quantum technology is the sensitivity of quantum states to noise. We propose a protocol that uses reverse dynamics to precisely control quantum systems against noise. By constructing the Petz recovery map, we explore the potential of using near-optimal recovery to control noisy quantum dynamics.
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Physical
Xuezhi Bian, Yanze Wu, Jonathan Rawlinson, Robert G. Littlejohn, Joseph E. Subotnik
Summary: This work presents a phase-space surface-hopping approach to simulate singlet-triplet intersystem crossing dynamics, and demonstrates that the relevant Berry curvature effects can be captured. This represents an important advancement in simultaneous simulation of photochemical and spin processes.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Physics, Applied
Xinyuan You, Ziwen Huang, Ugur Alyanak, Alexander Romanenko, Anna Grassellino, Shaojiang Zhu
Summary: This paper proposes a method to alleviate the limited coherence times in superconducting circuits by designing the noise spectral densities of quantum bits. Specifically, by depolarizing and dephasing the material defects, the high-frequency noise spectrum is smoothed and the low-frequency noise amplitude is suppressed, resulting in a stabilized qubit lifetime and an increased qubit pure dephasing time.
PHYSICAL REVIEW APPLIED
(2022)
Article
Chemistry, Physical
Xuezhi Bian, Yanze Wu, Hung-Hsuan Teh, Joseph E. Subotnik
Summary: The research presents a surface-hopping approach for modeling dynamics between multiple electronic states, focusing on Berry force effects and quasi-diabatic index application, capturing a significant amount of new physics.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
Moritz Heindl, Leticia Gonzalez
Summary: This study evaluates the capability of fewest-switches surface hopping (FSSH) in describing non-adiabatic dynamics under external fields, finding that FSSH is able to reproduce trends in multi-configurational time dependent Hartree (MCTDH) reference calculations but no ideal set of parameters exists. Adequate treatment of overcoherence in FSSH is crucial for improving the description of excitation processes.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Quantum Science & Technology
Atirach Ritboon, Lukas Slodicka, Radim Filip
Summary: The article explores the application of sequential
phonon measurements in quantum mechanical sensing, simulations and computing, specifically focusing on the motion of trapped atoms. By sequentially measuring force and heating, better sensitivity can be obtained from motional Fock states and quantum Fisher information can be saturated.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Review
Chemistry, Multidisciplinary
Oleg Prezhdo
Summary: Rapid, far-from-equilibrium processes are crucial in modern technologies, and are studied experimentally with various spectroscopies that track system evolution in ultrafast timescales. Non-adiabatic molecular dynamics provides insights at the atomistic level that mimic time-resolved experiments, enabling a deeper understanding of complex systems and processes.
ACCOUNTS OF CHEMICAL RESEARCH
(2021)
Article
Optics
T. Tassis, F. L. Semiao
Summary: Trapped ions driven by electromagnetic radiation are highly developed quantum technologies, ranging from proof-of-principle experiments to on-chip integration for quantum information units. With novel trap and cavity designs, faster quantum gates and state transfers become possible. However, there is currently limited knowledge on models and applications that go beyond the weak-driving scenario.
Article
Multidisciplinary Sciences
Rakshit Jain, Vishvendra S. Poonia, Kasturi Saha, Dipankar Saha, Swaroop Ganguly
Summary: Theoretical studies show that long-lived coherence in the radical pair system is unlikely in a multinuclear environment, and hyperfine anisotropy is essential for the necessary sensitivity of the compass. The research identifies a parameter regime where the compass can exhibit good sensitivity even without sustained electron spin coherence.
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2021)
Article
Multidisciplinary Sciences
Abdel-Baset A. Mohamed, Abdel-Haleem Abdel-Aty, Montasir Qasymeh, Hichem Eleuch
Summary: In this study, we explore the non-local correlation dynamics in a two-dimensional honeycomb lattice of disordered electrons in a Graphene sheet. The results show that the lattice-point interaction affects the Bell-function non-locality and entanglement concurrence, and the uncertainty-induced non-locality correlation is more stable than the Bell non-locality and concurrence.
SCIENTIFIC REPORTS
(2022)
Article
Optics
Arkaprabha Ghosal, Debarshi Das, Subhashish Banerjee
Summary: In this research, the efficacy of quantum resources for quantum teleportation were studied by considering the preparation of a pure two-qubit state and its transmission through a quantum channel. It was found that certain quantum channels have different effects on the utility of quantum teleportation depending on whether the initial state is maximally entangled or nonmaximally entangled. Additionally, nonunital channels were shown to be more effective than unital channels in producing useful states for universal quantum teleportation from nonmaximally entangled pure states.
Article
Chemistry, Physical
Aarti Sindhu, Amber Jain
Summary: The authors modified the augmented fewest switches surface hopping (A-FSSH) scheme to improve its efficiency without sacrificing accuracy. Comparing their proposed decoherence scheme to a recently proposed parameter-free scheme by Wang et al., they found that their scheme is at least 30 times more efficient than the original A-FSSH method while achieving comparable accuracy. Although Wang's scheme is more than ten times more efficient than theirs, it does not provide accurate results in the case of large diabatic coupling.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Tarni Aggarwal, Swaroop Ganguly, Dipankar Saha
Summary: This study explores the use of GaN-based quantum-confined structures with optical cavities for solid-state light sources. It reveals that variations in stoichiometry and the presence of recombination centers do not necessarily lead to sub-bandgap transitions, as trapped electrons can be recovered through Coulombic interaction. The presence of carrier reservoirs in the form of inhomogeneities can significantly reduce the efficacy of sub-bandgap transitions, as evidenced by time-resolved measurements.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Engineering, Electrical & Electronic
Bazila Parvez, Jaya Jha, Pankaj Upadhyay, Navneet Bhardwaj, Yogendra Yadav, Bhanu Upadhyay, Swaroop Ganguly, Dipankar Saha
Summary: Thinning of the SiC substrate has positive effects on the performance of AlGaN/GaN HEMTs, including reducing contact resistance, increasing mobility and saturation velocity, and decreasing 2DEG density. Overall, these effects collectively contribute to the performance improvement of the devices.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Jaya Jha, Swaroop Ganguly, Dipankar Saha
Summary: The development of GaN-based high electron mobility transistors (HEMTs) for radio-frequency and high power applications has been successful for n-type transistors, but remains challenging for p-type transistors. By using a p-doped InGaN/GaN superlattice (SL) structure, a GaN-based field-effect complementary transistor device can be realized to overcome these challenges.
Article
Nanoscience & Nanotechnology
Ankit Udai, Anthony Aiello, Tarni Aggarwal, Dipankar Saha, Pallab Bhattacharya
Summary: This study investigated the femtosecond carrier and photon dynamics in self-organized In0.27Ga0.73N/GaN QDs grown by molecular beam epitaxy. The unique phenomenon in the dynamics is attributed to the contrast in carrier density caused by the different effective masses of carriers.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Nanoscience & Nanotechnology
Sreenadh Surapaneni, Jaya Jha, Vikas Pendem, Yogendra Kumar Yadav, Swaroop Ganguly, Dipankar Saha
Summary: Transport in GaN-based nanoscale devices is crucial for various applications, but the understanding of one-dimensional transport is still in its early stages. The low-field mobility in these devices is influenced by acoustic phonon, polar optical phonon, and scattering from piezoelectric fields. Contrary to intuition, piezoelectric fields play a determining role in low-field regimes, leading to non-monotonic changes in mobility due to evolving density of states and 2D phonon confinement.
Article
Physics, Condensed Matter
Tarni Aggarwal, Ankit Udai, Debashree Banerjee, Vikas Pendem, Shonal Chouksey, Pratim Saha, Sandeep Sankaranarayanan, Swaroop Ganguly, Pallab Bhattacharya, Dipankar Saha
Summary: The ultrafast nonlinear carrier-photon dynamics of GaN-based optoelectronic devices with nanostructures are studied, focusing on the impact of excited-state dynamics on device performance. Experimental and theoretical research shows the importance of understanding carrier and photon dynamics in these nanostructures.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Vikas Pendem, Swaroop Ganguly, Dipankar Saha
Summary: In this study, we have investigated the fractional dimensional nature of experimental semiconductor quantum mechanical systems and its effect on the accurate prediction of electronic and optoelectronic properties. We have proposed a formalism to estimate the actual dimensionality of the system, which addresses the anomaly of using the conventional integer density of states (DOS). We have experimentally verified the formalism in AlGaN/GaN high electron mobility transistors (HEMTs) and observed a significant variation in dimensionality as the gate bias sweeps the channel from depletion to strong inversion. Furthermore, we have observed the manifestation of fractional dimension in AlGaN/GaN nanofins, which is verified experimentally through a shift in threshold voltage and the rate of conduction-band state filling. Thus, this efficient and accurate formalism enhances the accuracy of models by estimating the dimension of any quantum mechanical system.
IEEE TRANSACTIONS ON NANOTECHNOLOGY
(2022)
Article
Nanoscience & Nanotechnology
Tarni Aggarwal, Ankit Udai, Pratim K. Saha, Swaroop Ganguly, Pallab Bhattacharya, Dipankar Saha
Summary: Efficiency droop at high carrier-injection regimes is a concern in InGaN/GaN quantum-confined hetero-structure-based light-emitting diodes (LEDs). This study demonstrates a potential solution through the positive effects from an optical cavity in suppressing the Auger recombination rate and highlights its technological importance.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Materials Science, Multidisciplinary
Akhil S. Kumar, Swaroop Ganguly, Dipankar Saha
Summary: Through partial overlapping gate transistors, a trade-off can be found between gate leakage current, I-OFF, and I-ON/I-OFF.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2022)
Article
Engineering, Electrical & Electronic
M. Meer, P. Pohekar, B. Parvez, S. Ganguly, D. Saha
Summary: In this study, the thermal oxidation of nickel as gate dielectrics is used to improve the characteristics of GaN-based metal oxide semiconductor high electron mobility transistors (HEMTs). The use of NiO as the gate dielectric leads to significant improvements in drive current, transconductance, subthreshold swing, unity current gain frequency, and gate current leakage. Additionally, a positive shift in threshold voltage is observed for the NiO-based gate dielectric devices compared to the Schottky barrier HEMTs.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2022)
Article
Nanoscience & Nanotechnology
Ankit Udai, Swaroop Ganguly, Pallab Bhattacharya, Dipankar Saha
Summary: This study investigates the ultrafast carrier dynamics of bound states in In0.14Ga0.86N/GaN quantum wells using femtosecond transient absorption spectroscopy. It reveals that both the ground and excited states contribute to the overall dynamics, which can be decoupled in the absorption spectra and time-resolved dynamics.
Article
Materials Science, Multidisciplinary
Vivek Kumar Surana, Swaroop Ganguly, Dipankar Saha
Summary: This work demonstrates the performance improvements in AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) achieved by using low-temperature inductively coupled plasma chemical vapor deposited (ICP-CVD) silicon nitride (SiNx). The SiNx layer effectively increases the in-plane tensile strain in the AlGaN barrier layer, leading to enhanced conductivity and piezoelectric properties of the transistor.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2022)
Article
Engineering, Electrical & Electronic
Binit Mallick, Dipankar Saha, Anindya Datta, Swaroop Ganguly
Summary: In this study, a physics-based numerical modeling approach is proposed to analyze experimental time-dependent optical second harmonic generation data from an oxide/semiconductor (SiO2/Si) interface. The comprehensive numerical solution to the Poisson-Boltzmann equation is developed using the Newton-Raphson method at different time instances. It incorporates the trapping behavior of photo-excited charge carriers at the SiO2/Si interface, within the SiO2, and at the SiO2 surface, in order to model the second harmonic photon count data obtained from experiments. This method enables quantitative analysis of the interface, oxide, and surface charge densities, providing a contact-less and non-invasive optical technique for oxide/semiconductor interface characterization.
SOLID-STATE ELECTRONICS
(2023)
Article
Physics, Applied
Pratim K. Saha, Kanchan Singh Rana, Navneet Thakur, Bazila Parvez, Shazan Ahmad Bhat, Swaroop Ganguly, Dipankar Saha
Summary: In this study, room-temperature single-photon emission from an InGaN QD embedded in a GaN nanoneedle is demonstrated. Reproducible and uniform-sized QDs are formed in the needle structures through a series of nanofabrication process steps. The results show higher spectral purity and smaller values of the second-order correlation, indicating the usefulness of the methodology for quantum technologies.
APPLIED PHYSICS LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Binit Mallick, Dipankar Saha, Anindya Datta, Swaroop Ganguly
Summary: This article presents a non-destructive and contactless characterization method for semiconductor/dielectric interfaces based on optical second-harmonic generation (SHG) technique. It can measure the conduction band offset and quantitatively evaluate the charge densities at the interface. The method extracts the type of interface-trapped charge and qualitatively analyzes the variation in interface states and oxide surface state density. A developed optical setup is used to monitor the time-dependent SHG from the semiconductor/oxide interface, and a numerical solver is employed to model the experimental data and extract the electronic properties at the interface.
ACS APPLIED MATERIALS & INTERFACES
(2023)
