arXiv subjects

Shao-Ming Fei

Publications and source records attributed to Shao-Ming Fei.

At least 73 records · Page 4Linked to original sources

arXiv2025

Unified Construction of Genuine Multipartite Entanglement Measures Based on Geometric Mean and its Applications

Genuine multipartite entanglement (GME) is an important resource in quantum information processing. We systematically study the measures of GME based on the geometric mean of bi-partition entanglements and present a unified construction of GME measures, which gives rise to the widely used GME measures including GME concurrence, the convex-roof extended negativity of GME, the geometric measure of entanglement of GME. Our GME measures satisfy the desirable conditions such as scalability and smoothness. Moreover, we provide fidelity-based analytical lower bounds for our GME measures. Our bounds are tight and can be estimated experiment friendly without requiring quantum state tomography. Furthermore, we apply our results to study the dynamics of GME. We identify an initial condition that influences the sudden death of genuine quadripartite entanglement under individual non-Markovian processes. The GME of Dirac particles with Hawking radiation in the background of a Schwarzschild black hole is also investigated.

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arXiv2025

Entanglement certification from moments of positive maps

Entanglement certification is crucial in physical experiments, particularly when only partial knowledge of the quantum state is available. In this context, we present an entanglement criterion based on positive but not completely positive maps, which eliminates the need to identify eigenvalues of the output state. Notably, the Faddeev-LeVerrier algorithm establishes a relationship between the coefficients of characteristic polynomials and the moments of a matrix. This enables the existence of negative eigenvalues through the moments of the output state. The effectiveness of our criterion relies on the selection of positive maps, similar to the original positive maps criterion.

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arXiv2025

Variational-toolbox-based separability detection of multiqubit states

Parametrized quantum circuits (PQCs) are crucial in variational quantum algorithms. While it is commonly believed that the optimal PQC is solely used to reproduce the target state, we here reveal that the optimal PQC can also provide valuable insights into the state's properties. We propose variational toolboxes to identify the $k$-separability of pure states, with or without preparation noise, by checking the structure within the optimal PQCs. Additionally, we introduce adaptive optimization strategies to detect the $k$-separability of mixed states. Compared to fixed PQCs, our approach controls fewer parameters for low-rank states. Finally, we validate our methods through numerical demonstrations for various states.

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arXiv2025

Estimating the Schmidt numbers of quantum states via symmetric measurements

The Schmidt numbers quantify the entanglement degree of quantum states. Quantum states with high Schmidt numbers provide a larger advantage in various quantum information processing tasks compared to quantum states with low Schmidt numbers. We derive a Schmidt number criterion based on the trace norm of the correlation matrix obtained from symmetric measurements. We show that our result is more effective than and superior to existing Schmidt number criteria by detailed examples.

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arXiv2025

General quantum computation on photons assisted with double single-sided cavity system

We propose a physical system consisting of two optical cavities and a two-level system (TLS), which can be viewed as a double single-sided cavity system. The two cavities are crossed each other in a mutually perpendicular way and are both single-sided. The TLS is coupled to the two cavities. The universal input-output relation of the system, the reflection and transmission coefficients are derived by exploiting the probability amplitude method. Then by using the nitrogen-vacancy center instead of the TLS, we generate the controlled-phase gate and the controlled-controlled-phase gate on the photon qubits, with simple protocols that can be accomplished in both weak and strong coupling regimes. The protocols are shown to give rise to high fidelities and gate efficiencies.

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arXiv2025

Explicit Formulas for Estimating Trace of Reduced Density Matrix Powers via Single-Circuit Measurement Probabilities

In the fields of quantum mechanics and quantum information science, the traces of reduced density matrix powers play a crucial role in the study of quantum systems and have numerous important applications. In this paper, we propose a universal framework to simultaneously estimate the traces of the $2$nd to the $n$th powers of a reduced density matrix using a single quantum circuit with $n$ copies of the quantum state. Specifically, our approach leverages the controlled SWAP test and establishes explicit formulas connecting measurement probabilities to these traces. We further develop two algorithms: a purely quantum method and a hybrid quantum-classical approach combining Newton-Girard iteration. Rigorous analysis via Hoeffding inequality demonstrates the method's efficiency, requiring only $M=O\left(\frac{1}{ε^2}\log(\frac{n}δ)\right)$ measurements to achieve precision $ε$ with confidence $1-δ$. Additionally, we explore various applications including the estimation of nonlinear functions and the representation of entanglement measures. Numerical simulations are conducted for two maximally entangled states, the GHZ state and the W state, to validate the proposed method.

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arXiv2025

Experimental Characterization of Quantumness Using the Uncertainty Principle, Coherence, and Nonlocality

Heisenberg's uncertainty principle, coherence and Bell nonlocality have been individually examined through many experiments. In this Letter, we systematically characterize all of this quantumness in a unified manner. We first construct universal uncertainty relations to reveal intrinsic features of incompatible measurements, which include all the state-independent uncertainties as special cases. We further extend to witness both quantum coherence and Bell nonlocality. We finally perform experiments with unified two-photon states, and validate the uncertainty principle, coherence and Bell nonlocality within the experimental error. Our methods for witnessing quantumness are valuable in characterizing quantum correlations in quantum information processing.

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arXiv2025

Improving Quantum Battery Capacity in Tripartite Quantum Systems by Local Projective Measurements

The impact of local von Neumann measurements on quantum battery capacity is investigated in tripartite quantum systems. Two measurement-based protocols are proposed and the concept of optimal local projective operators is introduced. Specifically, explicit analytical expressions are derived for the protocols when applied to general three-qubit X-states. Furthermore, the negative effects of white noise and dephasing noise on quantum battery capacity are analyzed, proving that optimal local projective operators can improve the robustness of subsystem and total system capacity against both noise types for the general tripartite X-state. The performance of different schemes in capacity enhancement are numerically validated through detailed examples and it is found that these optimized operators can effectively enhance both subsystem and total system battery capacity. The results indicate that the local von Neumann measurement is a powerful tool to enhance the battery capacity in multipartite quantum systems.

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arXiv2025

Quantifying coherence of quantum channels based on the generalized $α$-$z$-relative Rényi entropy

By using the Choi-Jamiołkowski isomorphism, we propose a well-defined coherence measure of quantum channels based on the generalized $α$-$z$-relative Rényi entropy. In addition, we present an alternative coherence measure of quantum channels by quantifying the commutativity between the channels and the completely dephasing channels with the generalized $α$-$z$-relative Rényi entropy. Some elegant properties of the measures are illustrated in detail. Explicit formulas of these coherence measures are derived for some detailed typical quantum channels.

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arXiv2025

Coherence monotones of quantum channels based on two generalized quantum relative entropies

By using the Choi-Jamiołkowski isomorphism, we propose two classes of coherence monotones of quantum channels based on the unified $(r,s)$-relative entropy and the sandwiched Rényi relative entropy. Elegant properties of the coherence monotones for quantum channels are explored. Moreover, we present the upper bounds of the coherence monotones and derive the explicit formulas of the coherence monotones for qubit unitary channels.

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arXiv2025

A coherence monotone from Kirkwood-Dirac nonclassicality with respect to mutually unbiased bases

The Kirkwood-Dirac distribution, serving as an informationally complete representation of a quantum state, has recently garnered increasing attention. We investigate the Kirkwood-Dirac classicality with respect to mutually unbiased bases. For prime dimensional Hilbert spaces, {we demonstrate that a quantum state exhibits Kirkwood-Dirac classicality for two distinct sets of mutually unbiased bases $(A,B)$ and $(A,B')$ if and only if it is incoherent with respect to $A$}. We subsequently introduce a coherence monotone based on Kirkwood-Dirac nonclassicality with respect to mutually unbiased bases. Additionally, we establish that this coherence monotone can be expressed through weak values, suggesting that quantum coherence can be utilized to detect anomalous weak values.

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arXiv2025

Photonic Energy-Coherence Theorem and Experimental Validations

Wave-particle duality, intertwining two inherently contradictory properties of quantum systems, remains one of the most conceptually profound aspects of quantum mechanics. By using the concept of energy capacity, the ability of a quantum system to store and extract energy, we derive a device-independent uncertainty relation for wave-particle duality. This relation is shown to be independent of both the representation space and the measurement basis of the quantum system. Furthermore, we experimentally validate this wave-particle duality relation using a photon-based platform.

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arXiv2025

Genuine Multipartite Entanglement Measure Based on $α$-concurrence

Quantifying genuine entanglement is a crucial task in quantum information theory. Based on the geometric mean of bipartite $α$-concurrences among all bipartitions, we present a class of well-defined genuine multipartite entanglement (GME) measures G$α$C with one parameter $α$ for arbitrary multipartite states. We show that the G$α$C is of continuity for any multipartite pure states. By utilizing the related symmetry, analytical results of G$α$C are derived for any $n$-qubit GHZ states and W states, which show that the GHZ states are more genuinely entangled than the W states. With explicit examples, we demonstrate that the G$α$C can distinguish different GME states that other GME measures fail to. These results justify the potential applications of G$α$C in characterizing genuine multipartite entanglements.

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arXiv2025

Mutually unbiased measurements-induced lower bounds of concurrence

We propose a family of lower bounds for concurrence in quantum systems using mutually unbiased measurements, which prove more effective in entanglement estimation compared to existing methods. Through analytical and numerical examples, we demonstrate that these bounds outperform conventional approaches, particularly in capturing finer entanglement features. Additionally, we introduce separability criterions based on MUMs for arbitrary $d$-dimensional bipartite systems, the research results show that our criterion has more advantages than the existing criteria.

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arXiv2025

A note on the lower bounds of genuine multipartite entanglement concurrence

Quantum entanglement plays a pivotal role in quantum information processing. Quantifying quantum entanglement is a challenging and essential research area within the field. This manuscript explores the relationships between bipartite entanglement concurrence, multipartite entanglement concurrence, and genuine multipartite entanglement (GME) concurrence. We derive lower bounds on GME concurrence from these relationships, demonstrating their superiority over existing results through rigorous proofs and numerical examples. Additionally, we investigate the connections between GME concurrence and other entanglement measures, such as tangle and global negativity, in multipartite quantum systems.

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arXiv2025

Unconditional robustness of multipartite entanglement of superposition

We study the robustness of genuine multipartite entanglement and inseparability of multipartite pure states under superposition with product pure states. We introduce the concept of the maximal and the minimal Schmidt ranks for multipartite states. From the minimal Schmidt rank of the first order we present criterion of verifying unconditional robustness of genuine multipartite entanglement of multipartite pure states under superposition with product pure states. By the maximal Schmidt rank of the first order we verify the unconditional robustness of multipartite inseparability under superposition with product pure states. The number of product states superposed to a given entangled state which result in a separable state is investigated in detail. Furthermore, the minimal Schmidt ranks of the second order are also introduced to identify the unconditional robustness of an entangled state for tripartite inseparability.

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arXiv2025

Detectors for local discrimination of sets of generalized Bell states

A fundamental problem in quantum information processing is the discrimination among a set of orthogonal quantum states of a composite system under local operations and classical communication (LOCC). Corresponding to the LOCC indistinguishable sets of four ququad-ququad orthogonal maximally entangled states (MESs) constructed by Yu et al. [Phys. Rev. Lett. 109, 020506 (2012)], the maximum commutative sets (MCSs) were introduced as detectors for the local distinguishability of the set of generalized Bell states (GBSs), for which the detectors are sufficient to determine the LOCC distinguishability. In this work, we show how to determine all the detectors for a given GBS set. We construct also several 4-GBS sets without detectors, most of which are one-way LOCC indistinguishable and only one is one-way LOCC distinguishable, indicating that the detectors are not necessary for LOCC distinguishability. Furthermore, we show that for 4-GBS sets in quantum system $\mathbb{C}^{6}\otimes\mathbb{C}^{6}$, the detectors are almost necessary for one-way LOCC distinguishability, except for one set in the sense of local unitary equivalence. The problem of one-way LOCC discrimination of 4-GBS sets in $\mathbb{C}^{6}\otimes\mathbb{C}^{6}$ is completely resolved.

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arXiv2025

Bell-Mermin-Klyshko Inequalities and One-way Information Deficit of Dirac Fields in Noninertial Frames

We investigate the Bell-Mermin-Klyshko inequalities and the one-way information deficit of Dirac fields in noninertial frames, where the quantum correlations are shared between inertial and accelerated observers due to the Unruh effect. We derive partial analytical results for specific quantum states using the one-way information deficit. Additionally, we present numerical results for the Bell-Mermin-Klyshko inequalities. The study reveals the presence of Bell nonlocality and the significance of the one-way information deficit in relativistic quantum information.

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