A5059701819- Quantum Computing Algorithms and Architecture
- Quantum Information and Cryptography
- Quantum-Dot Cellular Automata
- Advanced Data Storage Technologies
- Quantum and electron transport phenomena
- Parallel Computing and Optimization Techniques
- Embedded Systems Design Techniques
- Semiconductor materials and devices
- Error Correcting Code Techniques
- Numerical Methods and Algorithms
- Cryptography and Data Security
- Cellular Automata and Applications
- Quantum Mechanics and Applications
Photon Etc (Canada)
2024
Universidad de Navarra
2020-2023
Quantum technologies have the potential to solve certain computationally hard problems with polynomial or super-polynomial speedups when compared classical methods. Unfortunately, unstable nature of quantum information makes it prone errors. For this reason, error correction is an invaluable tool make reliable and enable ultimate goal fault-tolerant computing. Surface codes currently stand as most promising candidates build near term corrected qubits given their two-dimensional architecture,...
Abstract The decoherence effects experienced by the qubits of a quantum processor are generally characterized using amplitude damping time ( T 1 ) and dephasing 2 ). Quantum channel models that exist at writing assume these parameters fixed invariant. However, recent experimental studies have shown they exhibit time-varying (TV) behaviour. These time-dependant fluctuations , which become even more pronounced in case superconducting qubits, imply conventional static do not capture noise...
It is the prevailing belief that quantum error correcting techniques will be required to build a utility-scale computer able perform computations are out of reach classical computers. The QECCs have been most extensively studied and therefore highly optimized, surface codes, extremely resource intensive in terms number physical qubits needed. A promising alternative, QLDPC has proposed more recently. These codes much less intensive, requiring up 10x fewer per logical qubit than practical...
The minimum weight perfect matching (MWPM) decoder is the standard decoding strategy for quantum surface codes. However, it suffers a harsh decrease in performance when subjected to biased or non-identical noise. In this work, we modify conventional MWPM so that considers biases, non-uniformities and relationship between $X$, $Y$ $Z$ errors of constituent qubits given code. Our modified approach, which refer as recursive decoder, obtains an $18\%$ improvement probability threshold $p_{th}$...
Commercially impactful quantum algorithms such as chemistry and Shor's algorithm require a number of qubits gates far beyond the capacity any existing processor. Distributed architectures, which scale horizontally by networking modules, provide route to commercial utility will eventually surpass capability single computing module. Such processors consume remote entanglement distributed between modules realize logic. Networked computers therefore rapidly distribute high fidelity modules. Here...
Quantum information is prone to suffer from errors caused by the so-called decoherence, which describes loss in coherence of quantum states associated their interactions with surrounding environment. This decoherence phenomenon present every task, be it transmission, processing or even storage information. Consequently, protection via error correction codes (QECC) paramount importance construct fully operational computers. Understanding environmental processes and way they are modeled...
Surface codes are generally studied based on the assumption that each of qubits make up surface code lattice suffers noise is independent and identically distributed (i.i.d.). However, real benchmarks individual relaxation ($T_1$) dephasing ($T_2$) times constituent state-of-the-art quantum processors have recently shown decoherence effects suffered by particular qubit actually vary in intensity. In consequence, this article we introduce non-identically (i.ni.d.) model, a model accounts for...
Time-varying quantum channels (TVQCs) have been proposed as a model to include fluctuations of the relaxation (${T}_{1}$) and dephasing times (${T}_{2}$). In previous works, realizations multiqubit TVQCs assumed be equal for all qubits an error correction block, implying that random variables describe ${T}_{1}$ ${T}_{2}$ are block-to-block uncorrelated but qubit-wise perfectly correlated same block. this article, we perform correlation analysis five processors. Our results show it is...
The well-documented capacity-approaching performance of sparse codes in the realm classical communications has inspired search for their quantum counterparts. Sparse are generally built as amalgamation two robust and decoded via decoding algorithms. However, paradigm presents phenomena that act a deleterious manner on when they based methodologies. One such phenomenon is known degeneracy, it major contributor to why do not entirely evoke stupendous error correcting abilities In this paper,...
Quantum low-density generator matrix (QLDGM) codes based on Calderbank-Steane-Shor (CSS) constructions have shown unprecedented error correction capabilities, displaying much improved performance in comparison to other sparse-graph codes. However, the nature of CSS designs and manner which they must be decoded limit that is attainable with are this construction. This motivates search for quantum code design strategies capable avoiding drawbacks associated In article, we introduce non-CSS...
The quantum paradigm presents a phenomenon known as degeneracy that can potentially improve the performance of error correcting codes. However, effects this mechanism are sometimes ignored when evaluating sparse codes and logical rate is not always correctly reported. In paper, we discuss previously existing methods to compute present an efficient coset-based method inspired by classical coding strategies estimate degenerate errors distinguish them from errors. Additionally, show proposed...
In this paper, we tackle the channel estimation problem for Pauli channels. Online methods depolarizing have been proposed in previous literature. However, realistic quantum devices often exhibit an asymmetric behaviour not captured by symmetric model, implying that method used Quantum Turbo Codes (QTC) should exploit such asymmetry error correcting operations to be successful. Consequently, propose online iterative aids successfully estimating each of individual probabilities associated...
Recent experimental studies have shown that the relaxation time ${T}_{1}$ and dephasing ${T}_{2}$ of superconducting qubits fluctuate considerably over time. Time-varying quantum channel (TVQC) models been proposed in order to consider time-varying nature parameters define qubit decoherence. This dynamic channels causes a degradation performance error correction codes (QECCs) is portrayed as flattening their rate curves. In this article we introduce concepts outage probability hashing...
Quantum low-density-generator-matrix (QLDGM) codes are known to exhibit great error correction capabilities, surpassing existing quantum low-density-parity-check (QLDPC) and other sparse-graph schemes over the depolarizing channel. Most of research on QLDPC (QEC) is conducted for symmetric instance generic Pauli channel, which incurs bit flips, phase or a combination both with same probability. However, due behavior materials they built from, some devices must be modelled using different...
Quantum Low Density Generator Matrix (QLDGM) codes based on Calderbank-Steane-Shor (CSS) constructions have shown unprecedented error correction capabilities in the paradigm of quantum communication. Recently, a strategy non-CSS derived from QLDGM CSS has been to surpass other Parity Check (QLDPC) schemes proposed literature over depolarizing channel. Given importance channel estimation and impact it performance QLDPC codes, this article, we study behaviour under umbrella mismatch. We begin...
Quantum technologies have the potential to solve computationally hard problems that are intractable via classical means. Unfortunately, unstable nature of quantum information makes it prone errors. For this reason, error correction is an invaluable tool make reliable and enable ultimate goal fault-tolerant computing. Surface codes currently stand as most promising candidates build corrected qubits given their two-dimensional architecture, a requirement only local operations, high tolerance...
Quantum computers herald the arrival of a new era in which previously intractable computational problems will be solved efficiently. However, quantum technology is held down by decoherence, phenomenon that omnipresent paradigm and renders information useless when left unchecked. The science error correction, discipline seeks to combine protect from effects decoherence using structures known as codes, has arisen meet this challenge. Stabilizer particular subclass have enabled fast progress...
Recent experimental studies have shown that the relaxation time ($T_1$) and dephasing ($T_2$) of superconducting qubits fluctuate considerably over time. To appropriately consider this time-varying nature $T_1$ $T_2$ parameters, a new class quantum channels, known as Time-Varying Quantum Channels (TVQCs), has been proposed. In previous works, realizations multi-qubit TVQCs assumed to be equal for all an error correction block, implying random variables describe fluctuations are...
The minimum weight perfect matching (MWPM) decoder is the standard decoding strategy for quantum surface codes. However, it suffers a harsh decrease in performance when subjected to biased or non-identical noise. In this work, we modify conventional MWPM so that considers biases, non-uniformities and relationship between $X$, $Y$ $Z$ errors of constituent qubits given code. Our modified approach, which refer as recursive decoder, obtains an $18\%$ improvement probability threshold $p_{th}$...
The quantum paradigm presents a phenomenon known as degeneracy that should improve the performance of error correcting codes. However, effects this mechanism are sometimes ignored when evaluating sparse codes and logical rate is not always correctly reported. In paper, we discuss previously existing methods to compute present an efficient coset-based method inspired by classical coding strategies estimate degenerate errors. Additionally, show proposed computational advantage for family...