Parity Measurements Research Articles

KAJIAN PROFIL RUJUKAN PADA KASUS PRE EKLAMSIA DI RSUD DATU SANGGUL RANTAU

One of the complications of pregnancy/delivery is pre-eclampsia/eclampsia. Objective is knowing the description of the referral profile in the case of pre-eclampsia at Datu Sanggul Rantau Hospital. Quantitative research was conducted in February 2023. The population was all pregnant, postpartum and postpartum women with pre-eclampsia cases from January 2021 - November 2022 totaling 122 cases. The total sampling technique was analyzed using univariate. The results of the study showed that the highest number of each characteristic was the origin of referrals, namely 84 people (69%), the highest number of referrals complete with officers and referral letters, namely 89 people (73%), the age of most respondents was in the risk category > 35 years 53 people (43%), the most gestational age was term term 83 people (68%), parity was primipara 53 people (43%), the stages of delivery in the mother during intrapartum were 76 people (62%), the classification of the diagnosis of pre eclampsia in cases of pre severe eclampsia, namely 86 people (70%) and the most pre-referral action was given pre-referral action, namely 82 people (67%). The conclusion is referral profile description consists of origin, of referral completeness of referral, age, gestational age, parity, diagnosis, and pre-referral measures.

Flip-Chip-Based Fast Inductive Parity Readout of a Planar Superconducting Island

The properties of superconducting devices depend sensitively on the parity (even or odd) of the quasiparticles that they contain. Encoding quantum information in the parity degree of freedom is central in several emerging solid-state qubit architectures, including in hybrid superconductor-semiconductor devices. In the latter case, accurate, nondestructive, and time-resolved parity measurements are a challenging issue. Here, we report on control and real-time parity measurement in a superconducting island embedded in a superconducting loop and realized in a hybrid two-dimensional heterostructure using a microwave resonator. To avoid microwave losses impeding time-resolved measurements, the device and readout resonator are located on separate chips, connected via flip-chip bonding, and couple inductively through vacuum. The superconducting resonator detects the parity-dependent circuit inductance, allowing for fast parity readout. We have resolved even- and odd-parity states with a signal-to-noise ratio of SNR≈3 for an integration time of 20μs and a detection fidelity exceeding 98%. The real-time parity measurement shows a state lifetime extending into the millisecond range. Our approach will lead to a better understanding of coherence-limiting mechanisms in superconducting quantum hardware and help to advance inductive-readout schemes for hybrid qubits. Published by the American Physical Society 2024

Controlling Majorana hybridization in magnetic chain-superconductor systems

We propose controlling the hybridization between Majorana zero modes at the ends of magnetic adatom chains on superconductors by an additional magnetic adatom deposited close by. By tuning the additional adatom's magnetization, position, and coupling to the superconductor, we can couple and decouple the Majorana modes, as well as control the ground-state parity. The scheme is independent of microscopic details in ferromagnetic and helical magnetic chains on superconductors, with and without spin-orbit coupling, which we show by studying their full microscopic models and their common low-energy description. Our results show that scanning tunneling microscopy and electron-spin-resonance techniques are promising tools for controlling the Majorana hybridization in magnetic adatoms-superconductor setups, providing a basis for Majorana parity measurements, fusion, and braiding techniques. Published by the American Physical Society 2024

Efficient and reliable detection of nonlocal quantum correlations in continuous-variable and hybrid states via random measurements

We investigate the violation of nonlocal realism using various entangled continues- and hybrid-variable states under dichotomic observables. In particular, we consider two cases of dichotomic observables (1) described by a pseudospin operator and (2) given in terms of the Wigner representation of the state in phase space, parity measurement and displacement operation. We address the recently proposed operational measure of nonlocality which describes the probability of local-realism violation under randomly sampled observables. We show the usefulness and limitations of the probability of local-realism violation for the detection of nonlocality. A simple procedure to detect such nonlocal correlations for randomly chosen settings with efficiencies of up to 100% is proposed. The practical advantage of applying random measurements that considerably lowers the experimental requirements is mentioned.

Generating magnon Bell states via parity measurement

We propose a scheme to entangle two magnon modes based on parity measurements. In particular, we consider a system that two yttrium-iron-garnet spheres are coupled to a V-type superconducting qutrit through the indirect interactions mediated by cavity modes. An effective parity-measurement operator that can project the two macroscopic spin systems to the desired subspace emerges when the ancillary qutrit is projected onto the ground state. Consequently, conventional and multi-excitation magnon Bell states can be generated from any separable states with a nonvanishing population in the desired subspace. The target state can be distilled with a near-to-unit fidelity only by several rounds of measurements and can be stabilized in the presence of the measurement imperfection and environmental decoherence. In addition, a single-shot version of our scheme is obtained by shaping the detuning between magnon and qutrit in the time domain. Our scheme that does not rely on any nonlinear Hamiltonian brings insights into the entangled-state generation in massive ferrimagnetic materials via quantum measurements.

Fast joint parity measurement via collective interactions induced by stimulated emission

Parity detection is essential in quantum error correction. Error syndromes coded in parity are detected routinely by sequential CNOT gates. Here, different from the standard CNOT-gate based scheme, we propose a reliable joint parity measurement (JPM) scheme inspired by stimulated emission. By controlling the collective behavior between data qubits and syndrome qubit, we realize the parity detection and experimentally implement the weight-2 and weight-4 JPM scheme in a tunable coupling superconducting circuit, which shows comparable performance to the CNOT scheme. Moreover, with the aid of the coupling tunability in quantum system, this scheme can be further utilized for specific joint entangling state preparation (JEP) with high fidelity, such as multiqubit entangled state preparation for non-adjacent qubits. This strategy, combined with the superconducting qubit system with tunable couplers, reveals tremendous potential and applications in the surface code architecture without adding extra circuit elements. Besides, the method we develop here can readily be applied in large-scale quantum computation and quantum simulation.

The role of the ratio of first trimester CRL (crown rump length) measurement to NT (nuchal translucency) measurements in predicting early-onset fetal growth restriction (FGR)

Objective: Our aim is to evaluate the role of the ratio of first-trimester CRL (crown rump length) measurement to NT (nuchal translucency) measurements in predicting early-onset fetal growth restriction (FGR) and to contribute to the existing literature.
 Methods: In the present case-control study, fetuses with early-onset FGR were compared to a frequency matched low risk control group. This study was conducted in the perinatology clinic of Ankara Bilkent City Hospital between 2020 and 2023. Maternal age, gravidity, parity, crown-rump length (CRL), and nuchal translucency (NT) measurements were compared between pregnant women with early onset FGR (n=39) and pregnant women without FGR (n=50).
 Results: The mean age of pregnant women with FGR who participated in the study was 27.1±0.8, and the mean age of pregnant women without FGR was 26.3±0.6, and no statistically significant difference was found between the two groups (p=0.4)). Mean CRL was 54.98±1.08 mm in the group with FGR and 56.99±1.11 mm in the group without FGR; there was no significant difference between the two groups (p=0.2). The NT value was 1.11 ± 0.04 mm in the FGR group and 1.13 ± 0.02 mm in the without FGR group, there was no significant difference between the two groups (p=0.73). The mean CRL/NT ratio was 52.00±2.33 in the group with early onset FGR and 51.46±1.48 in the group without FGR and there was no statistically significant difference between the two groups (p=0.83).
 When the early developing FGR group is evaluated within itself, the mean age at diagnosis was 31.7±0.3 weeks. EFW mean percentile at diagnosis was 4.5±0.6 and ac percentile was 2.9±0.4. The mean umbilical artery systole/diastole ratio (UA-SD) was 2.9±0.16 and the mean umbilical artery pulsatility index (UA-PI) was 1.02±0.05.
 Conclusion: Crown-rump length to nuchal translucency ratio is not clinically useful to predict early-onset FGR.

Charge Sensing the Parity of an Andreev Molecule

The proximity effect of superconductivity on confined states in semiconductors gives rise to various bound states such as Andreev bound states, Andreev molecules, and Majorana zero modes. While such bound states do not conserve charge, their fermion parity is a good quantum number. One way to measure parity is to convert it to charge first, which is then sensed. In this work, we sense the charge of Andreev bound states and Andreev molecules in an InSb-Al hybrid nanowire using an integrated quantum dot operated as a charge sensor. We show how charge sensing measurements can resolve the even and odd states of an Andreev molecule, without affecting the parity. Such an approach can be further used for parity measurements of Majorana zero modes in Kitaev chains based on quantum dots. Published by the American Physical Society 2024

CHSH Bell tests for optical hybrid entanglement

Optical hybrid entanglement can be created between two qubits, one encoded in a single photon and another one in coherent states with opposite phases. It opens the path to a variety of quantum technologies, such as heterogeneous quantum networks, merging continuous- and discrete-variable encoding, and enabling the transport and interconversion of information. However, reliable characterization of the non-local nature of this quantum state is limited so far to full quantum state tomography. Here, we perform a thorough study of Clauser–Horne–Shimony–Holt Bell inequality tests, enabling practical verification of quantum nonlocality for optical hybrid entanglement. We show that a practical violation of this inequality is possible with simple photon number on/off measurements if detection efficiencies stay above 82%. Another approach, based on photon-number parity measurements, requires 94% efficiency but works well in the limit of higher photon populations. Both tests use no postselection of the measurement outcomes and they are free of the fair-sampling hypothesis. Our proposal paves the way to performing loophole-free tests using feasible experimental tasks such as coherent state interference and photon counting.

Parity-enhanced quantum optimal measurements

In quantum metrology, measurement and estimation schemes are vital for achieving higher precision, along with initial state preparation. This article presents the compound measurement of parity and particle number, which is optimal for a broad range of states named equator states (ESs). ES encompasses most pure input states used in current studies and, more significantly, a wide range of mixed states. Moreover, the ES can be prepared directly using non-demolition parity measurement. We thus propose an improved quantum phase estimation protocol applicable to arbitrary input states, ensuring precision consistently surpassing that of the standard protocol. The proposed scheme is also demonstrated using a nonlinear interferometer, with the realization of the non-demolition parity measurement in atomic condensates.

High-performance repetition cat code using fast noisy operations

Bosonic cat qubits stabilized by two-photon driven dissipation benefit from exponential suppression of bit-flip errors and an extensive set of gates preserving this protection. These properties make them promising building blocks of a hardware-efficient and fault-tolerant quantum processor. In this paper, we propose a performance optimization of the repetition cat code architecture using fast but noisy CNOT gates for stabilizer measurements. This optimization leads to high thresholds for the physical figure of merit, given as the ratio between intrinsic single-photon loss rate of the bosonic mode and the engineered two-photon loss rate, as well as an improved scaling below threshold of the required overhead, to reach an expected level of logical error rate. Relying on the specific error models for cat qubit operations, this optimization exploits fast parity measurements, using accelerated low-fidelity CNOT gates, combined with fast ancilla parity-check qubits. The significant enhancement in the performance is explained by: 1- the highly asymmetric error model of cat qubit CNOT gates with a major component on control (ancilla) qubits, and 2- the robustness of the repetition cat code error correction performance in presence of the leakage induced by fast operations. In order to demonstrate these performances, we develop a method to sample the repetition code under circuit-level noise that also takes into account cat qubit state leakage.

A Pair Measurement Surface Code on Pentagons

In this paper, I present a way to compile the surface code into two-body parity measurements ("pair measurements"), where the pair measurements run along the edges of a Cairo pentagonal tiling. The resulting circuit improves on prior work by Chao et al. by using fewer pair measurements per four-body stabilizer measurement (5 instead of 6) and fewer time steps per round of stabilizer measurement (6 instead of 10). Using Monte Carlo sampling, I show that these improvements increase the threshold of the surface code when compiling into pair measurements from ≈0.2% to ≈0.4%, and also that they improve the teraquop footprint at a 0.1% physical gate error rate from ≈6000 qubits to ≈3000 qubits. However, I also show that the teraquop footprint of Chao et al's construction improves more quickly than mine as physical error rate decreases, and is likely better below a physical gate error rate of ≈0.03% (due to bidirectional hook errors in my construction). I also compare to the planar honeycomb code, showing that although this work does noticeably reduce the gap between the surface code and the honeycomb code (when compiling into pair measurements), the honeycomb code is still more efficient (threshold ≈0.8%, teraquop footprint at 0.1% of ≈1000).

Certifying the quantum Fisher information from a given set of mean values: a semidefinite programming approach

We introduce a semidefinite programming algorithm to find the minimal quantum Fisher information compatible with an arbitrary dataset of mean values. This certification task allows one to quantify the resource content of a quantum system for metrology applications without complete knowledge of the quantum state. We implement the algorithm to study quantum spin ensembles. We first focus on Dicke states, where our findings challenge and complement previous results in the literature. We then investigate states generated during the one-axis twisting dynamics, where in particular we find that the metrological power of the so-called multi-headed cat states can be certified using simple collective spin observables, such as fourth-order moments for small systems, and parity measurements for arbitrary system sizes.

Localization measures of parity adapted U(D)-spin coherent states applied to the phase space analysis of the D-level Lipkin-Meshkov-Glick model.

We study phase space properties of critical, parity symmetric, N-qudit systems undergoing a quantum phase transition (QPT) in the thermodynamic N→∞ limit. The D=3 level (qutrit) Lipkin-Meshkov-Glick model is eventually examined as a particular example. For this purpose, we consider U(D)-spin coherent states (DSCS), generalizing the standard D=2 atomic coherent states, to define the coherent state representation Q_{ψ} (Husimi function) of a symmetric N-qudit state |ψ〉 in the phase space CP^{D-1} (complex projective manifold). DSCS are good variational approximations to the ground state of an N-qudit system, especially in the N→∞ limit, where the discrete parity symmetry Z_{2}^{D-1} is spontaneously broken. For finite N, parity can be restored by projecting DSCS onto 2^{D-1} different parity invariant subspaces, which define generalized "Schrödinger cat states" reproducing quite faithfully low-lying Hamiltonian eigenstates obtained by numerical diagonalization. Precursors of the QPT are then visualized for finite N by plotting the Husimi function of these parity projected DSCS in phase space, together with their Husimi moments and Wehrl entropy, in the neighborhood of the critical points. These are good localization measures and markers of the QPT.

Phase sensitivity and entanglement of superposition coherent states in Mach–Zehnder interferometer

In this paper, we mainly focus on analyzing the fidelity, parity measurement, phase sensitivity and entanglement properties of the output states corresponding to three quantum superposition coherent states, i.e. even coherent state (ECS), Yurke-Stoler state (YSS) and odd coherent state (OCS). Our results show that the OCS characterizes super-resolution in the phase measurement via parity measurement at the output ports of a Mach–Zehnder interferometer. In addition, we find that the optimal phase sensitivity may approach the Heisenberg limit which is independent of the superposition coefficient of the coherent states. An interesting finding is that the macroscopically entangled coherent states can be experimentally prepared by adjusting the parameters of the nonlinear phase shifter of the MZI.

Improvement in phase-sensitivity of a Mach–Zehnder interferometer with the superposition of Schrödinger’s cat-like state with vacuum state as an input under parity measurement

Improvement in phase-sensitivity of a Mach–Zehnder interferometer with the superposition of Schrödinger’s cat-like state with vacuum state as an input under parity measurement

Fast high-fidelity parity measurement of spin qubits in quantum dots using modulated pulses

Spin qubits in semiconductor quantum dots are a promising candidate for scalable quantum computation. A key step in quantum error correction with spin qubits is the capability to perform high-fidelity parity measurement much faster than the coherence time and to generate entanglement deterministically. Here we propose a parity measurement scheme for two spin qubits by modulated pulses, using a superconducting resonator as a detector. We show that the distinction between spin-parity states can be achieved with a high fidelity within a short measurement time. The combination of parity measurement and feedback control allows the deterministic preparation of various spin entangled states. In addition, the method can be directly applied to parity measurements and surface codes of multiple spin qubits. These results pave the way for fault-tolerant quantum computation with spin qubits.

Measurement‐Based Hyperentanglement Distillation for Lossy and Distortion Photon State

AbstractThe information content of a photon system can be extended by hyperentanglement, but the quality of hyperentanglement will be decreased by the complicated transmission loss and channel noise in quantum information processing. Here, an efficient measurement‐based hyperentanglement distillation protocol (MB‐HDP) is presented for depressing the effects of complicated transmission loss and channel noise on hyperentanglement. In the MB‐HDP, the nonlocal lossy and distortion photon states are coupled to local hyperentangled Greenberger–Horne–Zeilinger (GHZ) states using parity measurement and qubit amplification device, and the decoherence caused by bit‐flip (phase‐flip) error, diverse transmission coefficients and transmission loss can be depressed by the successful measurement results, which can increase the quality of nonlocal hyperentangled photon state. This MB‐HDP broadens the application scope of hyperentanglement distillation to nonlocal lossy and distortion photon state with a lower degree of entanglement. In addition, the MB‐HDP can further improve the quality of nonlocal hyperentangled photon state by coupling multiple copies of lossy and distortion hyperentangled photon state with local hyperentangled GHZ states. This work demonstrates the ability of measurement‐based method for ensuring the quality of nonlocal hyperentanglement, which can improve the integrity and capacity of long‐distance quantum information processing.

New estimates of international capital mobility for select OECD economies

This paper offers a new perspective on the meaning and measure of international capital mobility (ICM), contributing to the literature in several ways. Using an extended international loanable funds framework, it reconciles traditional interest parity (IP) measures of ICM with the original Feldstein-Horioka measure. It proposes a novel macro-oriented approach to estimate the degree of ICM. Using quarterly data for the period 2000–2020 for select OECD economies, the study found that ICM is near perfect when capital inflows finance private investment, government spending, and consumption. Interest differentials, though significant, contribute minimally to explaining capital inflows, consistent with very high ICM for these economies.

Precise Nondestructive Parity Measurement of Artificial Atoms Using a Superconducting Resonator and Homodyne Measurement

AbstractIn this paper, a robust and accurate protocol is proposed to realize nondestructive parity measurement of artificial atoms using a superconducting resonator and homodyne measurement. With the help of an additional microwave driving field, the cavity field evolves into a coherent state or remains in a vacuum state according to the parity of the atoms. Consequently, the parity information of atoms can be read out by a homodyne measurement on the cavity. Parity information can be obtained without destroying the original state of the system, which means that the state can be further applied to other quantum information processing tasks after a parity measurement. The numerical simulation results show that the protocol is robust against systematic error, random noise, and decoherence. Therefore, this protocol can provide a feasible viewpoint for nondestructive parity measurement.