Alejandro Grajales Dau
A5091247691- Quantum Computing Algorithms and Architecture
- Quantum Information and Cryptography
- Quantum and electron transport phenomena
- Quantum many-body systems
- Advancements in Semiconductor Devices and Circuit Design
- Neural Networks and Reservoir Computing
- Semiconductor materials and devices
- Quantum optics and atomic interactions
- Neural Networks and Applications
- Theoretical and Computational Physics
- Quantum Mechanics and Applications
- Advanced Data Storage Technologies
- Ultrasonics and Acoustic Wave Propagation
- Topological Materials and Phenomena
- Non-Destructive Testing Techniques
- Quantum-Dot Cellular Automata
- Computational Physics and Python Applications
- Quantum, superfluid, helium dynamics
- Computational Geometry and Mesh Generation
- Mechanical and Optical Resonators
- Algebraic structures and combinatorial models
- Physics of Superconductivity and Magnetism
- Complex Network Analysis Techniques
- Advanced Thermodynamics and Statistical Mechanics
- Random lasers and scattering media
Google (United States)
2022-2025
University of California, Riverside
2022
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
Understanding universal aspects of quantum dynamics is an unresolved problem in statistical mechanics. In particular, the spin one-dimensional Heisenberg model were conjectured as to belong Kardar-Parisi-Zhang (KPZ) universality class based on scaling infinite-temperature spin-spin correlation function. a chain 46 superconducting qubits, we studied probability distribution magnetization transferred across chain's center, [Formula: see text]. The first two moments text] show superdiffusive...
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...
Undesired coupling to the surrounding environment destroys long-range correlations in quantum processors and hinders coherent evolution nominally available computational space. This noise is an outstanding challenge when leveraging computation power of near-term
Abstract Understanding how interacting particles approach thermal equilibrium is a major challenge of quantum simulators 1,2 . Unlocking the full potential such systems towards this goal requires flexible initial state preparation, precise time evolution and extensive probes for final characterization. Here we present simulator comprising 69 superconducting qubits that supports both universal gates high-fidelity analogue evolution, with performance beyond reach classical simulation in...
Inherent symmetry of a quantum system may protect its otherwise fragile states. Leveraging such protection requires testing robustness against uncontrolled environmental interactions. Using 47 superconducting qubits, we implement the one-dimensional kicked Ising model which exhibits non-local Majorana edge modes (MEMs) with $\mathbb{Z}_2$ parity symmetry. Remarkably, find that any multi-qubit Pauli operator overlapping MEMs uniform late-time decay rate comparable to single-qubit relaxation...
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...
Undesired coupling to the surrounding environment destroys long-range correlations on quantum processors and hinders coherent evolution in nominally available computational space. This incoherent noise is an outstanding challenge fully leverage computation power of near-term processors. It has been shown that benchmarking Random Circuit Sampling (RCS) with Cross-Entropy Benchmarking (XEB) can provide a reliable estimate effective size Hilbert space coherently available. The extent which...
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...
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...
Quantum error correction provides a path to reach practical quantum computing by combining multiple physical qubits into logical qubit, where the rate is suppressed exponentially as more are added. However, this exponential suppression only occurs if below critical threshold. In work, we present two surface code memories operating threshold: distance-7 and distance-5 integrated with real-time decoder. The of our larger memory factor $\Lambda$ = 2.14 $\pm$ 0.02 when increasing distance two,...
An important measure of the development quantum computing platforms has been simulation increasingly complex physical systems. Prior to fault-tolerant computing, robust error mitigation strategies are necessary continue this growth. Here, we study within seniority-zero electron pairing subspace, which affords both a computational stepping stone fully correlated model, and an opportunity validate recently introduced ``purification-based'' error-mitigation strategies. We compare performance...
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...
Understanding how interacting particles approach thermal equilibrium is a major challenge of quantum simulators. Unlocking the full potential such systems toward this goal requires flexible initial state preparation, precise time evolution, and extensive probes for final characterization. We present simulator comprising 69 superconducting qubits which supports both universal gates high-fidelity analog with performance beyond reach classical simulation in cross-entropy benchmarking...
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...
Understanding universal aspects of quantum dynamics is an unresolved problem in statistical mechanics. In particular, the spin 1D Heisenberg model were conjectured to belong Kardar-Parisi-Zhang (KPZ) universality class based on scaling infinite-temperature spin-spin correlation function. a chain 46 superconducting qubits, we study probability distribution, $P(\mathcal{M})$, magnetization transferred across chain's center. The first two moments $P(\mathcal{M})$ show superdiffusive behavior,...