Alexander T. Lill
A5020760755- Quantum Computing Algorithms and Architecture
- Quantum Information and Cryptography
- Organic Electronics and Photovoltaics
- Conducting polymers and applications
- Quantum many-body systems
- Advancements in Semiconductor Devices and Circuit Design
- Quantum and electron transport phenomena
- Neural Networks and Reservoir Computing
- Semiconductor materials and devices
- Advanced Memory and Neural Computing
- Quantum Mechanics and Applications
- Advanced Data Storage Technologies
- Quantum optics and atomic interactions
- Organic Light-Emitting Diodes Research
- Ultrasonics and Acoustic Wave Propagation
- Luminescence and Fluorescent Materials
- Non-Destructive Testing Techniques
- Theoretical and Computational Physics
- Advanced Sensor and Energy Harvesting Materials
- Neural Networks and Applications
- Perovskite Materials and Applications
- Synthetic Organic Chemistry Methods
- Photochromic and Fluorescence Chemistry
- Random lasers and scattering media
- Photonic Crystals and Applications
Google (United States)
2022-2025
University of California, Santa Barbara
2017-2023
University of California, Riverside
2022
University of California System
2020
Santa Barbara City College
2020
University of California, Santa Cruz
2014
Abstract Practical quantum computing will require error rates well below those achievable with physical qubits. Quantum correction 1,2 offers a path to algorithmically relevant by encoding logical qubits within many qubits, for which increasing the number of enhances protection against errors. However, introducing more also increases sources, so density errors must be sufficiently low performance improve code size. Here we report measurement qubit scaling across several sizes, and...
Indistinguishability of particles is a fundamental principle quantum mechanics
Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for simulation of high-temperature superconductivity or magnetism. Using up 49 superconducting qubits, we prepared low-energy transverse-field Ising model through coupling auxiliary qubits. In one dimension, observed long-range correlations and a ground-state fidelity 0.86 18 qubits at critical point. two dimensions, found mutual information that extends beyond...
Systems of correlated particles appear in many fields modern science and represent some the most intractable computational problems nature. The challenge these systems arises when interactions become comparable to other energy scales, which makes state each particle depend on all particles1. lack general solutions for three-body problem acceptable theory strongly electrons shows that our understanding fades number or interaction strength increases. One hallmarks interacting is formation...
Abstract An important measure of the development quantum computing platforms has been simulation increasingly complex physical systems. Before fault-tolerant computing, robust error-mitigation strategies were necessary to continue this growth. Here, we validate recently introduced that exploit expectation ideal output a algorithm would be pure state. We consider task simulating electron systems in seniority-zero subspace where all electrons are paired with their opposite spin. This affords...
We demonstrate a high dynamic range Josephson parametric amplifier (JPA) in which the active nonlinear element is implemented using an array of rf-SQUIDs. The device matched to 50 Ω environment with Klopfenstein-taper impedance transformer and achieves bandwidth 250–300 MHz input saturation powers up −95 dBm at 20 dB gain. A 54-qubit Sycamore processor was used benchmark these devices, providing calibration for readout power, estimation added noise, platform comparison against standard...
Solution-processed organic field-effect transistors (OFETs) were fabricated with the addition of an salt, trityl tetrakis(pentafluorophenyl)borate (TrTPFB), into thin films donor-acceptor copolymer semiconductors. The performance OFETs is significantly enhanced after salt incorporated. TrTPFB confirmed to p-dope semiconductors used in this study, and doping efficiency as well physics was investigated. In addition, systematic electrical structural characterizations reveal how enhances OFETs....
Abstract PCPDTBT‐SO 3 K (CPE‐K), a conjugated polyelectrolyte, is presented as mixed conductor material that can be used to fabricate high transconductance accumulation mode organic electrochemical transistors (OECTs). OECTs are utilized in wide range of applications such analyte detection, neural interfacing, impedance sensing, and neuromorphic computing. The use interdigitated contacts enable relatively small device area comparison standard demonstrated. Such characteristics highly desired...
Abstract The field effect transistor (FET) is arguably one of the most important circuit elements in modern electronics. Recently, a need has developed for flexible electronics variety emerging applications. Examples include form‐fitting healthcare‐monitoring devices, displays, and radio frequency identification tags. Organic FETs (OFETs) are viable candidates producing such devices because they incorporate semiconducting π‐conjugated materials, including small molecules conjugated polymers,...
A novel wide-gap conjugated polymer PhF2,5 (Eg = 1.9 eV) is designed to contain alternating cyclopentadithiophene and difluorophenylene unit with the goal of favoring unipolar organic field effect transistor characteristics. The higher lowest unoccupied molecular orbital energy increases barrier electron injection, leading transport on/off ratios, without sacrificing desirable high hole mobilities.
Tetracyanoquinodimethane leads to trap-enhanced photoconductive gain and highly efficient broadband sensing for bulk heterojunction organic photodetectors.
Practical quantum computing will require error rates that are well below what is achievable with physical qubits. Quantum correction offers a path to algorithmically-relevant by encoding logical qubits within many qubits, where increasing the number of enhances protection against errors. However, introducing more also increases sources, so density errors must be sufficiently low in order for performance improve code size. Here, we report measurement qubit scaling across multiple sizes, and...
Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for simulation of high-temperature superconductivity or magnetism. Using up 49 superconducting qubits, we prepared low-energy transverse-field Ising model through coupling auxiliary qubits. In one dimension, observed long-range correlations and a ground-state fidelity 0.86 18 qubits at critical point. two dimensions, found mutual information that extends beyond...
A detailed study of a high-k fluoropolymer gate dielectric material, poly(vinylidene fluoride-co-hexafluoropropylene) [P(VDF-HFP)], is presented as guide to achieve low operational voltage and electrically stable device performance. The large dipole moment C–F dipoles in P(VDF-HFP) responsible for its high constant well potentially ferroelectric behavior that must be minimized avoid hysteretic current–voltage characteristics. range material grades processing conditions are explored shown...
Electrical instability and nonideality due to undesirable electron injection are often‐encountered problems for high‐mobility organic field‐effect transistors (OFETs) with low‐bandgap polymer semiconductors. Due trapping the resulting accumulation of negative charges on silicon dioxide dielectric, transfer curves deviate from ideality characteristics double‐slopes observed as devices operated extended periods time. One way circumvent those is use an electron‐acceptor additive, such fullerene...
Abstract The molecular structure and electrical properties of two n‐type organic small molecules which have the same core but different alkyl chains are compared. effect length on charge transport along alkyl‐chain stacking direction (out‐of‐plane) is investigated by a combination techniques. results show that longer chain corresponds to lower out‐of‐plane mobility ( µ ). More importantly, it found this not only plays significant role in affecting performance diode‐structure devices such as...
Abstract Measurement has a special role in quantum theory 1 : by collapsing the wavefunction it can enable phenomena such as teleportation 2 and thereby alter "arrow of time" that constrains unitary evolution. When integrated many-body dynamics, measurements lead to emergent patterns information space-time 3-10 go beyond established paradigms for characterizing phases, either or out equilibrium 11-13 . On present-day NISQ processors 14 , experimental realization this physics is challenging...
Varied-length conjugated polyelectrolytes (2–5 methylene units) containing CPDT- alt -BT were synthesized to study the optical, electrochemical, and morphological properties. These used in accumulation mode organic electrochemical transistors.
Leakage of quantum information out computational states into higher energy represents a major challenge in the pursuit error correction (QEC). In QEC circuit, leakage builds over time and spreads through multi-qubit interactions. This leads to correlated errors that degrade exponential suppression logical with scale, challenging feasibility as path towards fault-tolerant computation. Here, we demonstrate execution distance-3 surface code distance-21 bit-flip on Sycamore processor where is...
Indistinguishability of particles is a fundamental principle quantum mechanics. For all elementary and quasiparticles observed to date - including fermions, bosons, Abelian anyons this guarantees that the braiding identical leaves system unchanged. However, in two spatial dimensions, an intriguing possibility exists: non-Abelian causes rotations space topologically degenerate wavefunctions. Hence, it can change observables without violating indistinguishability. Despite well developed...
Measurement has a special role in quantum theory: by collapsing the wavefunction it can enable phenomena such as teleportation and thereby alter "arrow of time" that constrains unitary evolution. When integrated many-body dynamics, measurements lead to emergent patterns information space-time go beyond established paradigms for characterizing phases, either or out equilibrium. On present-day NISQ processors, experimental realization this physics is challenging due noise, hardware...
Abstract Ion‐free organic ratchets with asymmetric injecting contacts (AICs) are fabricated using solution‐processable semiconductors. Scanning Kelvin probe microscopy analysis reveals that the rectifying function is achieved via “charge pump” mechanism. Electrical characterizations show device can readily operate under industrial standard radio frequency and its high‐frequency performance may be enhanced through further material/device engineering. The built‐in feature exempts devices from...