arXiv subjects

Hao-Sheng Zeng

Publications and source records attributed to Hao-Sheng Zeng.

At least 19 recordsLinked to original sources

arXiv2024

Curvature-enhanced multipartite coherence in the multiverse

Here, we study quantum coherence of N-partite GHZ (Greenberger-Horne-Zeilinger) and W states in the multiverse consisting of N causally disconnected de Sitter spaces. Interestingly, N-partite coherence increases monotonically as the curvature increases, while the Unruh effect destroys multipartite coherence in Rindler spacetime. Conversely, the curvature effect destroys quantum entanglement and discord, meaning that the curvature effect is beneficial to quantum coherence and harmful to quantum correlations in the multiverse. We find that, with the increase of n expanding de Sitter spaces, N-partite coherence of GHZ state increases monotonically for any curvature, while quantum coherence of the W state decreases or increases monotonically depending on the curvature. We find a distribution relationship, which indicates that the correlated coherence of N-partite W state is equal to the sum of all bipartite correlated coherence in the multiverse. Multipartite coherence exhibits unique properties in the multiverse, which argues that it may provide some evidence for the existence of the multiverse.

gr-qc↗

arXiv2024

Does anti-Unruh effect assist quantum entanglement and coherence?

In this paper, we use the concepts of quantum entanglement and coherence to analyze the Unruh and anti-Unruh effects based on the model of Unruh-DeWitt detector. For the first time, we find that (i) the Unruh effect reduces quantum entanglement but enhances quantum coherence; (ii) the anti-Unruh effect enhances quantum entanglement but reduces quantum coherence. This surprising result refutes the notion that the Unruh effect can only destroy quantum entanglement and coherence simultaneously, and that the anti-Unruh can only protect quantum resources. Consequently, it opens up a new source for discovering experimental evidence supporting the existence of the Unruh and anti-Unruh effects.

gr-qc↗

arXiv2024

Gaussian quantum steering in multi-event horizon spacetime

We study Gaussian quantum steering in the Schwarzschild-de Sitter (SdS) spacetime that is endowed with both a black hole event horizon (BEH) and a cosmological event horizon (CEH), giving rise to two different Hawking temperatures. It is shown that the Hawking effect of the black hole always reduces the quantum steering, but the Hawking effect of the expanding universe does not always play the same role. For the first time, we find that the Hawking effect can improve quantum steering. We also find that the observer who locates in the BEH has stronger steerability than the observer who locates in CEH. Further, we study the steering asymmetry, and the conditions for two-way, one-way and no-way steering in the SdS spacetime. Finally, we study the Gaussian quantum steering in the scenario of effective equilibrium temperature. We show that quantum steering reduces monotonically with the effective temperature but now increases monotonically with the Hawking temperature of the black hole, which banishes the belief that the Hawking effect can only destroy quantum steering.

quant-ph↗

arXiv2023

Does Hawking effect always degrade fidelity of quantum teleportation in Schwarzschild spacetime?

Previous studies have shown that the Hawking effect always destroys quantum correlations and the fidelity of quantum teleportation in the Schwarzschild black hole. Here, we investigate the fidelity of quantum teleportation of Dirac fields between users in Schwarzschild spacetime. We find that, with the increase of the Hawking temperature, the fidelity of quantum teleportation can monotonically increase, monotonically decrease, or non-monotonically increase, depending on the choice of the initial state, which means that the Hawking effect can create net fidelity of quantum teleportation. This striking result banishes the extended belief that the Hawking effect of the black hole can only destroy the fidelity of quantum teleportation. We also find that quantum steering cannot fully guarantee the fidelity of quantum teleportation in Schwarzschild spacetime. This new unexpected source may provide a new idea for the experimental evidence of the Hawking effect.

gr-qc↗

arXiv2023

Quantum coherence and interference in Young's experiments

We propose the concept of pair-wise coherence to study the relation between the l1 norm of coherence and the quantum interference in Young's multi-photon multi-path experiments, where the input photons may be entangled each other. We find that only the local coherence of each single photon can make quantum interference and the collective coherence between photons has no contribution to quantum interference. The visibility of interference fringe is commonly less than the l1norm of coherence of the corresponding input state, suggesting that the l1 norm of coherence is only the necessary but not sufficient condition for quantum interference. We also find that the maximal fringe visibility can reach one. The optimal input states for producing the maximal visibility are presented.

quant-ph↗

arXiv2023

Would quantum coherence be increased by curvature effect in de Sitter space?

We study the quantum coherence in de Sitter space for the bipartite system of Alice and Bob who initially share an entangled state between the two modes of a free massive scalar field. It is shown that the space-curvature effect can produce both local coherence and correlated coherence, leading to the increase of the total coherence of the bipartite system. These results are sharp different from the Unruh effect or Hawking effect, which, in the single mode approximation, cannot produce local coherence and at the same time destroy correlated coherence, leading to the decrease of the total coherence of the bipartite systems. Interestingly, we find that quantum coherence has the opposite behavior compared with the quantum correlation in de Sitter space. We also find that quantum coherence is most severely affected by the curvature effect of de Sitter space for the cases of conformal invariance and masslessness. Our result reveals the difference between the curvature effect in the de Sitter space and the Unruh effect in Rindler spacetime or the Hawking effect in black hole spacetime on quantum coherence.

gr-qc↗

arXiv2023

Genuine tripartite entanglement of W state subject to Hawking effect of a Schwarzschild black hole

We study the genuine tripartite entanglement (GTE), one-tangle and two-tangle of W state of fermionic fields in the background of a Schwarzschild black hole. We find that, with the increase of the Hawking temperature, the GTE of W state first decreases and then tends to zero, while the GTE of GHZ state first decreases and then freezes. We also find that the Hawking effect can completely destroy the two-tangle of W state, whilie one-tangle first decreases and then appears freezing phenomenon with the growth of the Hawking temperature. These results are helpful to guide us to select appropriate quantum states and quantum resources to deal with relativistic quantum information tasks.

quant-ph↗

arXiv2022

Fermionic steering and its monogamy relations in Schwarzschild spacetime

Using two different types of quantification for quantum steering, we study the influence of Hawking radiation on quantum steering for fermionic fields in Schwarzschild spacetime. The degradation for the steering between physically accessible observers and the generation for the steering between physically accessible and inaccessible observers induced by Hawking radiation are studied. We also reveal the difference between the two types of quantification for steering, and find some monogamy relations between steering and entanglement. Furthermore, we show the different properties between fermionic steering and bosonic steering in Schwarzschild spacetime.

quant-ph↗

arXiv2022

Genuine multipartite entanglement subject to the Unruh and anti-Unruh effects

We study the acceleration effect on the genuine tripartite entanglement for one or two accelerated detector(s) coupled to the vacuum field. Surprisingly, we findthatthe increase anddecrease in entanglement have no definite correspondence with the Unruh and anti-Unruh effects. Specifically, Unruh effect can not only decrease but also enhance the tripartite entanglement between detectors; also, anti-Unruh effect can not only enhance but also decrease the tripartite entanglement. We give an explanation of this phenomenon. Finally, we extend the discussion from tripartite to N-partite systems.

quant-ph↗

arXiv2022

Quantum correlation between a qubit and a relativistic boson in an expanding spacetime

We use the quantumcorrelation of both logarithmic negativity andmutual information between a qubit and a relativistic boson to analyze the dynamics of Universe expansion. These dynamical quantum correlations can encode the information about underlying spacetime structure, which suggests a promising application in observational cosmology. We find that the dynamics of both logarithmic negativity and mutual information between the qubit and the boson are very similar. They decrease monotonically with the growth of the expansion volume and the expansion rate. Smaller momentum and medium-sized mass of boson are more favourable for extracting the information about history of Universe expansion. The quantum correlation between the qubit and the antiboson however has very different behavior: the logarithmic negativity is always zero and the mutual information can be generated through the expansion of Universe. Smaller momentum and medium-sized mass of antiboson are beneficial for the production of mutual information. Finally, the trigger phenomenon and conservation for mutual information are witnessed.

quant-ph↗

arXiv2022

Genuine N-partite entanglement and distributed relationships in the background of dilation black holes

With the complexity of information tasks, the bipartite and tripartite entanglement can no longer meet our needs, and we need more entangled particles to process relativistic quantum information. In this paper, we study the genuine N-partite entanglement and distributed relationships for Dirac fields in the background of dilaton black holes. We present the general analytical expression including all physically accessible and inaccessible entanglement in curved spacetime. We find that the accessible N-partite entanglement exhibits irreversible decoherence as the increase of black hole's dilaton, and on the other hand the inaccessible N-partite entanglement increases from zero monotonically or non-monotonically, depending on the relative numbers of the accessible to the inaccessible modes, which forms a sharp contrast with the cases of bipartite and tripartite entanglement where the inaccessible entanglement increase only monotonically. We also find two distributed relationships between accessible and inaccessible N-partite entanglement in curved spacetime. The results give us a new understanding of the Hawking radiation.

quant-ph↗

arXiv2022

Schwinger effect of Gaussian correlations in constant electric fields

We study the Schwinger effect of Gaussian correlations (quantum entanglement, discord and mutual information) of the continuous-variable two-mode squeezed states shared by Alice and Bob, paying special attention to the difference of the Schwinger effect of correlations between modes of fermion-fermion and qubit-bosonic fields studied previously. We also study the redistribution and conservativeness of the correlations under the Schwinger effect.

quant-ph↗

arXiv2022

Genuine tripartite nonlocality and entanglement in curved spacetime

We study the genuine tripartite nonlocality (GTN) and the genuine tripartite entanglement (GTE) of Dirac fields in the background of a Schwarzschild black hole. We find that the Hawking radiation degrades both the physically accessible GTN and the physically accessible GTE. The former suffers from "sudden death" at some critical Hawking temperature, and the latter approaches to the nonzero asymptotic value in the limit of infinite Hawking temperature. We also find that the Hawking effect cannot generate the physically inaccessible GTN, but can generate the physically inaccessible GTE for fermion fields in curved spacetime. These results show that on the one hand the GTN cannot pass through the event horizon of black hole, but the GTE do can, and on the other hand the surviving physically accessible GTE and the generated physically inaccessible GTE for fermions in curved spacetime are all not nonlocal. Some monogamy relations between the physically accessible GTE and the physically inaccessible GTE are found.

quant-ph↗

arXiv2022

Quantum coherence and distribution of N-partite bosonic fields in noninertial frame

We study the quantum coherence and its distribution of N-partite GHZ and W states of bosonic fields in the noninertial frames with arbitrary number of acceleration observers. We find that the coherence of both GHZ and W state reduces with accelerations and freezes in the limit of infinite accelerations. The freezing value of coherence depends on the number of accelerated observers. The coherence of N-partite GHZ state is genuinely global and no coherence exists in any subsystems. For the N-partite W state, however, the coherence is essentially bipartite types, and the total coherence is equal to the sum of coherence of all the bipartite subsystems.

quant-ph↗

arXiv2017

Non-Markovian dynamics and quantum interference of open three-level quantum systems

The exactly analytical solutions for the dynamics of the dissipative three-level V-type and $Λ$-type atomic systems in the vacuum Lorentzian environments are presented. Quantum interference phenomenon between the two transitions in V-type atomic system is studied and the intuitive interference conditions are derived. For the dissipative $Λ$-type atomic system, we demonstrate that the similar quantum interference phenomenon does not exist. Finally, we study the dynamical evolution of quantum Fisher information, quantum entanglement and quantum coherence for the V-type atomic system. We find that quantum interference plays a positive role to the protection of quantum entanglement and quantum coherence. The difference between the two typical measures of the quantum coherence is also demonstrated in the considered systems.

quant-ph↗

arXiv2013

Improving the quality of spatial quantum channels

We show, for the non-Markovian or time-dependent Markovian process, by breaking up a spatial quantum channel (SQC) into a series of periodically arranged sub-components, that the quality of information transmission described by the purity, fidelity and concurrence of the output states can be improved. The relation to the quantum zero effect and possible applications of the idea have been discussed.

quant-ph↗

arXiv2013

Correlation quantum beats induced by non-Markovian effect

For two qubits independently coupled to their respective structured reservoirs (Lorentzian spectrum), quantum beats for entanglement and discord are found which are the result of quantum interference between correlation oscillations induced by local non-Markovian environments. We also discuss the preservation of quantum correlations by the effective suppression of the spontaneous emission.

quant-ph↗

arXiv2012

Non-Markovian dynamics for an open two-level system without rotating wave approximation: Indivisibility versus backflow of information

By use of the two measures presented recently, the indivisibility and the backflow of information, we study the non-Markovianity of the dynamics for a two-level system interacting with a zero-temperature structured environment without using rotating wave approximation (RWA). In the limit of weak coupling between the system and the reservoir, and by expanding the time-convolutionless (TCL) generator to the forth order with respect to the coupling strength, the time-local non-Markovian master equation for the reduced state of the system is derived. Under the secular approximation, the exact analytic solution is obtained and the sufficient and necessary conditions for the indivisibility and the backflow of information for the system dynamics are presented. In the more general case, we investigate numerically the properties of the two measures for the case of Lorentzian reservoir. Our results show the importance of the counter-rotating terms to the short-time-scale non-Markovian behavior of the system dynamics, further expose the relations between the two measures and their rationality as non-Markovian measures. Finally, the complete positivity of the dynamics of the considered system is discussed.

quant-ph↗