arXiv subjects

Ji-Bing Yuan

Publications and source records attributed to Ji-Bing Yuan.

14 recordsLinked to original sources

arXiv2025

On-Demand Control of Input-State-Dependent Single-Photon Scattering in Multi-Mode Waveguides

Precise control of a single photon transport in broadband, multi-mode waveguides is a fundamental challenge for scalable quantum networks. We propose a theoretical scheme for on-demand control of single-photon scattering using a driven $Λ$-type emitter coupled to a rectangular waveguide. By employing the Lippmann-Schwinger formalism, we derive the exact analytical scattering matrix and reveal two key interference mechanisms: electromagnetically induced transparency for complete transmission and Fano resonance for complete reflection. We demonstrate that the single-photon scattering is dynamically engineered by the driving field, enabling a switch between complete transmission and dual-frequency complete reflection. Crucially, in the multi-mode regime, we show that the scattering is governed by quantum interference between modes, making it critically dependent on the input photonic state. By preparing the photon in a specific coherent superposition state, the multi-mode interference is harnessed to achieve Fano resonance-mediated complete reflection. Conversely, a single-mode input suppresses complete reflection. This input-state-dependent scattering establishes a general framework for multi-mode quantum photonics, paving the way for broadband dual-frequency filters, multi-mode quantum routers, and on-chip spectrometers.

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arXiv2024

Antisymmetry-breaking-coupling-enhanced sensing of quantum reservoirs

We investigate the utilization of a single generalized dephasing qubit for sensing a quantum reservoir, where the antisymmetric coupling between the qubit and its reservoir is broken. It is found that in addition to the decay factor encoding channel, the antisymmetric coupling breaking gives rise to another phase factor encoding channel. We introduce an optimal measurement for the generalized dephasing qubit which enables the practical measurement precision to reach the theoretical ultimate precision quantified by the quantum signal-to-noise ratio (QSNR). As an example, the generalized dephasing qubit is employed to estimate the $s$-wave scattering length of an atomic Bose-Einstein condensate. It is found that the phase-induced QSNR caused by the antisymmetric coupling breaking is at least two orders of magnitude higher than the decay-induced QSNR at the millisecond timescale and the optimal relative error can achieve a scaling $\propto 1/t$ with $t$ being the encoding time in long-term encoding. Our work opens a way for supersensitive sensing of quantum reservoirs.

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arXiv2024

Utilizing encoding time as a resource to enhance quantum sensing by probe qubit dephasing

We examine a system in which an impurity qubit is immersed in a quasi-two-dimensional dipolar Bose-Einstein condensate whose collective excitations act as a depasing reservoir for the qubit. The relative dipole-dipole interaction strength is estimated by the probe qubit dephasing. The ultimate precision of this estimation is quantified by the quantum Fisher information, which can be obtained by means of measuring quantum coherence of the probe qubit. Our findings indicate that, in the interval where roton excitations appear, the quantum Fisher information oscillates periodically with the encoding time $t$, and the amplitude of these oscillations increases alongside the extension of $t$. Moreover, we analytically determine that the envelope curve formed by the local maximum points satisfies the functional relationship $At+Bt^{1/2}+C$ during long-term encoding scenarios, where $A$, $B$, $C$ are positive numbers. It is also revealed that the highly non-Markovian effects caused by the roton softening of the excitation spectrum allow long encoding time to serve as a resource for enhancing sensing precision. Our work provides a new pathway for enhancing the sensing precision of dephasing qubits.

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arXiv2022

Quantum sensing of temperature close to absolute zero in a Bose-Einstein condensate

We propose a theoretical scheme for quantum sensing of temperature close to absolute zero in a quasi-one-dimensional Bose-Einstein condensate (BEC). In our scheme, a single-atom impurity qubit is used as a temper-ature sensor. We investigate the sensitivity of the single-atom sensor in estimating the temperature of the BEC. We demonstrate that the sensitivity of the temperature sensor can saturate the quantum Cramer-Rao bound by means of measuring quantum coherence of the probe qubit. We study the temperature sensing performance by the use of quantum signal-to-noise ratio (QSNR). It is indicated that there is an optimal encoding time that the QSNR can reach its maximum in the full-temperature regime. In particular, we find that the QSNR reaches a finite upper bound in the weak coupling regime even when the temperature is close to absolute zero, which implies that the sensing-error-divergence problem is avoided in our scheme. Our work opens a way for quantum sensing of temperature close to absolute zero in the BEC.

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arXiv2020

Supersensitive estimation of the coupling rate in cavity optomechanics with an impurity-doped Bose-Einstein condensate

We propose a scheme to implement a supersensitive estimation of the coupling strength in a hybrid optomechanical system which consists of a cavity-Bose-Einstein condensate system coupled to an impurity. This method can dramatically improve the estimation precision even when the involved photon number is small. The quantum Fisher information indicates that the Heisenberg scale sensitivity of the coupling rate could be obtained when the photon loss rate is smaller than the corresponding critical value in the input of either coherent state or squeezed state. The critical photon decay rate for the coherent state is larger than that of the squeezed state, and the coherent state input case is more robust against the photon loss than the squeezed state case. We also present the measurement scheme which can saturate the quantum Cramér-Rao bound.

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arXiv2018

Near-Heisenberg-limited parameter estimation precision by a dipolar-Bose-gas reservoir engineering

We propose a scheme to obtain the Heisenberg-limited parameter estimation precision by immersing atoms in a thermally equilibrated quasi-one-dimensional dipolar Bose-Einstein condensate reservoir. We show that the collisions between the dipolar atoms and the immersed atoms can result in a controllable nonlinear interaction through tuning the relative strength and the sign of the dipolar and contact interaction. We find that the repulsive dipolar interaction reservoir is preferential for the spin squeezing and the appearance of an entangled non-Gaussian state. As a useful resource for quantum metrology, we also show that the non-Gaussian state results in the phase estimation precision in the Heisenberg scaling, outperforming that of the spin-squeezed state.

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arXiv2015

Manipulation of tripartite-to-bipartite entanglement localization under quantum noises and its application to entanglement distribution

This paper is to investigate the effects of quantum noises on entanglement localization by taking an example of reducing a three-qubit Greenberger-Horne-Zeilinger (GHZ) state to a two-qubit entangled state. We consider, respectively, two types of quantum decoherence, i.e., amplitude-damping and depolarizing decoherence, and explore the best von Neumann measurements on one of three qubits of the triple GHZ state for making the amount of entanglement of the collapsed bipartite state be as large as possible. The results indicate that different noises have different impacts on entanglement localization, and that the optimal strategy for reducing a three-qubit GHZ state to a two-qubit one via local measurements and classical communications in the amplitude-damping case is different from that in the noise-free case. We also show that the idea of entanglement localization could be utilized to improve the quality of bipartite entanglement distributing through amplitude-damping channels. These findings might shed a new light on entanglement manipulations and transformations.

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arXiv2014

Entanglement-enhanced two-photon delocalization in a coupled-cavity array

We study transport properties of two entangled photons which are initially injected into two nearest-neighbor coupling cavities in a one-dimensional coupled-cavity array (CCA). It is found that photonic transport dynamics in the two-photon CCA exhibits entanglement-enhanced two-photon delocalization (TPD) phenomenon. It is shown that the CCA can realize the localization-to-delocalization transition for two entangled photons.

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arXiv2013

Quantum-discord-induced superradiance and subradiance in a system of two separated atoms

We investigate collective radiant properties of two separated atoms in X-type quantum states. We show that quantum correlations measured by quantum discord (QD) can induce and enhance superradiance and subradiance in the two-atom system even though in the absence of interatomic quantum entanglement. We also explore quantum statistical properties of photons in the superradiance and subradiance by addressing the second-order correlation function. In particular, when the initial state of the two separated atoms is the Werner state with non-zero QD, we find that radiation photons in the superradiant region exhibit the nonclassical sub-Poissonian statistics and the degree of the sub-Poissonian statistics increases with increasing of the QD amount, while radiation photons in the subradiant region have either the sub-Poissonian or super-Poissonian statistics depending on the amount of QD and the directional angle. In the subradiant regime we predict the QD-induced photon statistics transition from the super-Poissonian to sub-Poissonian statistics. These results shed a new light on applications of QD as a quantum resource.

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arXiv2013

Impurity-induced Dicke quantum phase transition in an impurity-doped cavity-Bose-Einstein condensate

We present a new generalized Dicke model, an impurity-doped Dicke model (IDDM), by the use of an impurity-doped cavity-Bose-Einstein condensate. It is shown that the impurity atom can induce Dicke quantum phase transition (QPT) from the normal phase to superradiant phase at a critic value of the impurity population. It is found that the IDDM exhibits continuous Dicke QPT with an infinite number of critical points, which is significantly different from that observed in the standard Dicke model with only one critical point. It is revealed that the impurity-induced Dicke QPT can happen in an arbitrary coupling regime of the cavity field and atoms while the Dicke QPT in the standard Dicke model occurs only in the strong coupling regime of the cavity field and atoms. This opens a way to observe the Dicke QPT in the intermediate and even weak coupling regime of the cavity field and atoms.

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arXiv2013

Nonmaximally entangled states can be better for quantum correlation distribution and storage

For carrying out many quantum information protocols entanglement must be established in advance between two distant parties. Practically, inevitable interaction of entangled subsystems with their environments during distribution and storage will result in degradation of entanglement. Here we investigate the decoherence of two-qubit entangled states in the local amplitude noise. We show that there exists a set of partially entangled states that are more robust than maximally entangled states in terms of the residual quantum correlation measured by concurrence, fully entangled fraction, and quantum discord. This result indicates that nonmaximally entangled states can outperform maximally entangled states for quantum correlation distribution and storage under the amplitude damping. It also educes a notable consequence that the ordering of states under quantum correlation monotones can be reversed even by local trace-preserving and completely positive maps.

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arXiv2012

Quantum discord amplification induced by quantum phase transition via a cavity-Bose-Einstein-condensate system

We propose a theoretical scheme to realize a sensitive amplification of quantum discord (QD) between two atomic qubits via a cavity-Bose-Einstein condensate (BEC) system which was used to firstly realize the Dicke quantum phase transition (QPT) [Nature 464, 1301 (2010)]. It is shown that the influence of the cavity-BEC system upon the two qubits is equivalent to a phase decoherence environment. It is found that QPT in the cavity-BEC system is the physical mechanism of the sensitive QD amplification.

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arXiv2011

Decoherence-free dynamics of quantum discord for two correlated qubits in finite-temperature reservoirs

We investigate decoherence-free evolution (DFE) of quantum discord (QD) for two initially-correlated qubits in two finite-temperature reservoirs using an exactly solvable model. We study QD dynamics of the two qubits coupled to two independent Ohmic reservoirs when the two qubits are initially prepared in X-type quantum states. It is found that reservoir temperature significantly affects the DFE dynamics. We show that it is possible to control the DFE and to prolong the DFE time by choosing suitable parameters of the two-qubit system and reservoirs.

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arXiv2010

Amplification of quantum discord between two uncoupled qubits in a common environment by phase decoherence

We study analytically the dynamic behaviors of quantum correlation measured by quantum discord between two uncoupled qubits, which are immersed in a common Ohmic environment. We show that the quantum discord of the two noninteracting qubits can be greatly amplified or protected for certain initially prepared $X$-type states in the time evolution. Especially, it is found that there does exist the stable amplification of the quantum discord for the case of two identical qubits, and the quantum discord can be protected for the case of two different qubits with a large detuning. It is also indicated that in general there does exist a sudden change of the quantum discord in the time evolution at a critic time point $t_c$, and the discord amplification and protection may occur only in the time interval $0<t\leq t_c$ for certain $X$-type states. This sheds new light on the creation and protection of quantum correlation.

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