Non-Markovian noise sources for quantum error mitigation

Reducing the impact of errors and decoherence in near-term quantum computers, such as noisy intermediate-scale quantum (NISQ) devices, is critical for their practical implementation. These factors significantly limit the applicability of quantum algorithms, necessitating a comprehensive understanding of their physical origins to establish effective error mitigation strategies. In this study, we present a non-Markovian model of quantum state evolution and a quantum error mitigation cost function tailored for NISQ devices interacting with an environment represented by a set of simple harmonic oscillators as a noise source. Employing the projection operator formalism and both advanced and retarded propagators in time, we derive the reduced-density operator for the output quantum states in a time-convolutionless form by solving the quantum Liouville equation. We examine the output quantum state fluctuations for both identity and controlled-NOT (CNOT) gate operations in two-qubit operations using a range of input states. Subsequently, these results are compared with experimental data from ion-trap and superconducting quantum computing systems to estimate the crucial parameters of the cost functions for quantum error mitigation. Our findings reveal that the cost function for quantum error mitigation increases as the coupling strength between the quantum system and its environment intensifies. This study underscores the significance of non-Markovian models in understanding quantum state evolution and highlights the practical implications of the quantum error mitigation cost function when assessing experimental results from NISQ devices

T-count optimization of approximate quantum Fourier transform

The quantum Fourier transform (QFT) is a ubiquitous quantum operation that is used in numerous quantum computing applications. The major obstacle to constructing a QFT circuit is that numerous elementary gates are required. Among the elementary gates, T gates dominate the cost of fault-tolerant implementation. Currently, the smallest-known T-count required to construct an n-qubit QFT circuit approximated to error O(\varepsilon) is ~8nlog_2(n/\varepsilon). Moreover, the depth of T gates (T-depth) in the approximate QFT circuit is ~2nlog_2(n/\varepsilon). This approximate QFT circuit was constructed using Toffoli gates and quantum adders. In this study, we present a new n-qubit QFT circuit approximated to error O(\varepsilon). Our approximate QFT circuit shows a T-count of ~4nlog_2(n/\varepsilon) and a T-depth of ~nlog_2(n/\varepsilon). Toffoli gates, which account for half of the T-count in the approximate QFT circuit reported in the previous study, are unnecessary in our construction. Quantum adders, which dominate the leading order term of T-depth in our approximate QFT circuit, are arranged in parallel to reduce T-depth

Reducing CNOT count in quantum Fourier transform for the linear nearest-neighbor architecture

Abstract Physical limitations of quantum hardware often necessitate nearest-neighbor (NN) architecture. When synthesizing quantum circuits using the basic gate library, which consists of CNOT and single-qubit gates, CNOT gates are required to convert a quantum circuit into one suitable for an NN architecture. In the basic gate library, CNOT gates are considered the primary cost of quantum circuits due to their higher error rates and longer execution times compared to single-qubit gates. In this paper, we propose a new linear NN (LNN) circuit design for quantum Fourier transform (QFT), one of the most versatile subroutines in quantum algorithms. Our LNN QFT circuit has only about 40% of the number of CNOT gates compared to previously known LNN QFT circuits. Subsequently, we input both our QFT circuits and conventional QFT circuits into the Qiskit transpiler to construct QFTs on IBM quantum computers, which necessitate NN architectures. Consequently, our QFT circuits demonstrate a substantial advantage over conventional QFT circuits in terms of the number of CNOT gates. This outcome implies that the proposed LNN QFT circuit design could serve as a novel foundation for developing QFT circuits implemented in quantum hardware that demands NN architecture

Liquidity creation or de-creation: evidence from US property and liability insurance industry

[[abstract]]Purpose – The purpose of this study is two-fold. The first purpose is to properly measure the level of US property and liability (P/L) insurers liquidity creation, applying the liquidity creation measure developed by Berger and Bouwman. The second purpose is to identify factors affecting P/L insurers' liquidity creation using a regression. Particularly, this paper tests two competing hypotheses regarding the relationship between the level of capital and liquidity creation. Design/methodology/approach – The paper calculates liquidity creation for the US P/L insurers. First, the paper categorizes all items in assets, liabilities and surplus into liquid, semi-liquid, or illiquid. This process is based on the ease, cost, and time for insurers to meet their contractual obligation to obtain liquid funds or to pay off their liability. The paper also constructs the regression model to test the impact of insurers' surplus level on liquidity creation while controlling for the firm-specific variables. The paper examines this relationship for the time period between 1998 and 2007. Findings – Contrary to the study of depository institutions, the paper reports that P/L insurers are liquidity destroyers than liquidity creators. This paper also provides that liquidity destruction varies over time and differs among insurers in different size. The total amount of liquidity destruction ranges from 47 to 58 percent of insurer total asset. In addition, the results of a regression show that insurer capital is negatively related to the level of liquidity creation. This provides implications that insurers with lower level of capital face more regulatory requirements and are forced to meet liquidity demand more. Practical implications – The level of liquidity creation and the trend of liquidity creation of P/L insurers are of particular interest to regulators and consumers because the level of liquidity creation as shown during the financial crisis has a significant adverse impact on the financial intermediaries. Originality/value – The paper do not aware of any study that attempts to measure liquidity creation by insurers and its relationship with both organizational and financial characteristics. The paper reports that P/L insurers are, unlike depository institutions, liquidity destroyers. Whether or not P/L insurers create/destroy liquidity is an interesting economic question to shed light on the roles of P/L insurers as a financial intermediary.[[notice]]補正完畢[[journaltype]]國外[[ispeerreviewed]]Y[[booktype]]紙本[[booktype]]電子版[[countrycodes]]GB

Liquidity transformation: an examination of US life insurers

[[abstract]]Purpose – The purpose of this paper is twofold: first, this paper measures how much liquidity is transformed by the US life insurance industry for the sample period; and Second, this study tests the “risk absorption” hypothesis and “financial fragility-crowding out” hypothesis to identify the impact of capital on liquidity creation in the US life insurance industry. In addition, a regression model is conducted to explore the relationship between liquidity creation and other firm characteristics. Design/methodology/approach – In order to construct the liquidity creation measures, all assets and liabilities are classified as liquid, semi-liquid, or illiquid with appropriate weights to these classifications, which will then be combined to measure the amount of liquidity creation. In addition, a regression model is analyzed. The level of insurers’ liquidity creation is regressed on the capital ratio (surplus over total assets) and other financial and organizational variables to test two prevailing hypotheses. Findings – This paper finds that the US life insurers de-create liquidity. The authors provide that the amount of liquidity de-creation is related to the size of insurers such that liquidity de-creation has increased as assets grow and that large insurers de-create most of liquidity. The US life insurance industry de-created $2.1 trillion in liquidity, i.e., 43 percent of total industry assets, in 2008. The empirical results support the “financial fragility-crowding out” hypothesis. Life insurers’ liquidity de-creation is mainly caused by the large portion of liquid assets, which is required by regulation and capital is not a main factor of liquidity de-creation. Originality/value – There is no known study on the issue of liquidity creation by life insurers. Thus, the extent of liquidity creation by the life insurance industry, if any, is an empirical matter to investigate, but also an important matter to regulators and the academia since the products and business operations (e.g. asset portfolio and asset and liability management) of life insurers are different from those of property and liability insurers.[[notice]]補正完

Individual and population diversity of 20 representative olfactory receptor genes in pigs

Abstract Understanding the influence of genetic variations in olfactory receptor (OR) genes on the olfaction-influenced phenotypes such as behaviors, reproduction, and feeding is important in animal biology. However, our understanding of the complexity of the OR subgenome is limited. In this study, we analyzed 1120 typing results of 20 representative OR genes belonging to 13 OR families on 14 pig chromosomes from 56 individuals belonging to seven different breeds using a sequence-based OR typing method. We showed that the presence of copy number variations, conservation of locus-specific diversity, abundance of breed-specific alleles, presence of a loss-of-function allele, and low-level purifying selection in pig OR genes could be common characteristics of OR genes in mammals. The observed nucleotide sequence diversity of pig ORs was higher than that of dogs. To the best of our knowledge, this is the first report on the individual- or population-level characterization of a large number of OR family genes in livestock species

Protegrin-1 cytotoxicity towards mammalian cells positively correlates with the magnitude of conformational changes of the unfolded form upon cell interaction

Porcine protegrin-1 (PG-1) is a broad-spectrum antimicrobial peptide (AMP) with potent antimicrobial activities. We produced recombinant PG-1 and evaluated its cytotoxicity toward various types of mammalian cell lines, including embryonic fibroblasts, retinal cells, embryonic kidney cells, neuroblastoma cells, alveolar macrophage cells, and neutrophils. The sensitivity of the different mammalian cells to cytotoxic damage induced by PG-1 differed significantly among the cell types, with retinal neuron cells and neutrophils being the most significantly affected. A circular dichroism analysis showed there was a precise correlation between conformational changes in PG-1 and the magnitude of cytotoxicity among the various cell type. Subsequently, a green fluorescent protein (GFP) penetration assay using positively charged GFPs indicated there was a close correlation between the degree of penetration of charged GFP into cells and the magnitude of PG-1 cytotoxicity. Furthermore, we also showed that inhibition of the synthesis of anionic sulphated proteoglycans on the cell surface decreases the cytotoxic damage induced by PG-1 treatment. Taken together, the observed cytotoxicity of PG-1 towards different membrane surfaces is highly driven by the membrane's anionic properties. Our results reveal a possible mechanism underlying cell-type dependent differences in cytotoxicity of AMPs, such as PG-1, toward mammalian cells.publishe

Population differentiated copy number variation between Eurasian wild boar and domesticated pig populations

Abstract Sus scrofa is a globally distributed livestock species that still maintains two different ways of life: wild and domesticated. Herein, we detected copy number variation (CNV) of 328 animals using short read alignment on Sscrofa11.1. We compared CNV among five groups of porcine populations: Asian domesticated (AD), European domesticated (ED), Asian wild (AW), European wild (EW), and Near Eastern wild (NEW). In total, 21,673 genes were identified on 154,872 copy number variation region (CNVR). Differences in gene copy numbers between populations were measured by considering the variance-based value $${V}_{ST}$$ V ST and the one-way ANOVA test followed by Scheffe test. As a result, 111 genes were suggested as copy number variable genes. Abnormally gained copy number on EEA1 in all populations was suggested the presence of minor CNV in the reference genome assembly, Sscrofa11.1. Copy number variable genes were related to meat quality, immune response, and reproduction traits. Hierarchical clustering of all individuals and mean pairwise $${V}_{ST}$$ V ST in breed level were visualized genetic relationship of 328 individuals and 56 populations separately. Our findings have shown how the complex history of pig evolution appears in genome-wide CNV of various populations with different regions and lifestyles

Tracing the Origin of the RSPO2 Long-Hair Allele and Epistatic Interaction between FGF5 and RSPO2 in Sapsaree Dog

Genetic analysis of the hair-length of Sapsaree dogs, a Korean native dog breed, showed a dominant mode of inheritance for long hair. Genome-Wide Association Study (GWAS) analysis and subsequent Mendelian segregation analysis revealed an association between OXR1, RSPO2, and PKHD1L1 on chromosome 13 (CFA13). We identified the previously reported 167 bp insertion in RSPO2 3’ untranslated region as a causative mutation for hair length variations. The analysis of 118 dog breeds and wolves revealed the selection signature on CFA13 in long-haired breeds. Haplotype analysis showed the association of only a few specific haplotypes to the breeds carrying the 167 bp insertion. The genetic diversity in the neighboring region linked to the insertion was higher in Sapsarees than in other Asian and European dog breeds carrying the same variation, suggesting an older history of its insertion in the Sapsaree genome than in that of the other breeds analyzed in this study. Our results show that the RSPO2 3’ UTR insertion is responsible for not only the furnishing phenotype but also determining the hair length of the entire body depending on the genetic background, suggesting an epistatic interaction between FGF5 and RSPO2 influencing the hair-length phenotype in dogs

High-Quality Nucleic Acid Isolation from Hard-to-Lyse Bacterial Strains Using PMAP-36, a Broad-Spectrum Antimicrobial Peptide

The efficiency of existing cell lysis methods to isolate nucleic acids from diverse bacteria varies depending on cell wall structures. This study tested a novel idea of using broad-spectrum antimicrobial peptides to improve the lytic efficiency of hard-to-lyse bacteria and characterized their differences. The lysis conditions of Staphylococcus aureus using recombinant porcine myeloid antimicrobial peptide 36 (PMAP-36), a broad-spectrum pig cathelicidin, was optimized, and RNA isolation was performed with cultured pellets of ten bacterial species using various membranolytic proteins. Additionally, three other antimicrobial peptides, protegrin-1 (PG-1), melittin, and nisin, were evaluated for their suitability as the membranolytic agents of bacteria. However, PMAP-36 use resulted in the most successful outcomes in RNA isolation from diverse bacterial species. The amount of total RNA obtained using PMAP-36 increased by ~2-fold compared to lysozyme in Salmonella typhimurium. Streptococci species were refractory to all lytic proteins tested, although the RNA yield from PMAP-36 treatment was slightly higher than that from other methods. PMAP-36 use produced high-quality RNA, and reverse transcription PCR showed the efficient amplification of the 16S rRNA gene from all tested strains. Additionally, the results of genomic DNA isolation were similar to those of RNA isolation. Thus, our findings present an additional option for high quality and unbiased nucleic acid isolation from microbiomes or challenging bacterial strains