arXiv subjects

Guang Ping He

Publications and source records attributed to Guang Ping He.

At least 19 recordsLinked to original sources

arXiv2026

Anomalous nonlocality of information masked in quantum correlations

Although information, strictly speaking, is not a physical entity, it generally requires physical entities as its carriers, e.g., writing it down on paper, encoding it with quantum particles, or transmitting it using electro-magnetic fields. And it seems natural that these carriers cannot travel faster than light. Here we reveal that if we use quantum correlations as the carrier of information (either quantum or classical), then it can display a kind of nonlocality, which bears both similarities to and distinctions from the nonlocality of physical particles. Notably, though superluminal signaling is still not allowed so that the special relativity is not violated, it is possible to select at our will whether to decode the information at one location, or to dispatch it to another location far away (i.e., to give up the chance of decoding the information and let it be decodable in somewhere else only) without needing the assistance of classical information, so that it occurs instantaneously without being limited by the speed of light. This phenomenon differs sharply from the nonlocality of physical particles that we once knew, where whether a particle can be detected in one location or another is governed by quantum uncertainty, which cannot be chosen freely.

quant-ph↗

arXiv2025

Solving the encoding bottleneck: of the HHL algorithm, by the HHL algorithm

The Harrow-Hassidim-Lloyd (HHL) algorithm offers exponential speedup for solving the quantum linear-system problem. But some caveats for the speedup could be hard to met. One of the difficulties is the encoding bottleneck, i.e., the efficient preparation of the initial quantum state. To prepare an arbitrary $N$-dimensional state exactly, existing state-preparation approaches generally require a runtime of $O(N)$, which will ruin the speedup of the HHL algorithm. Here we show that the states can be prepared approximately with a runtime of $O(poly(\log N))$ by employing a slightly modified version of the HHL algorithm itself. Thus, applying this approach to prepare the initial state of the original HHL algorithm can preserve the exponential speedup advantage. It can also serve as a standalone solution for other applications demanding fast state preparation.

quant-ph↗

arXiv2024

Training quantum machine learning models on cloud without uploading the data

Based on the linearity of quantum unitary operations, we propose a method that runs the parameterized quantum circuits before encoding the input data. This enables a dataset owner to train machine learning models on quantum cloud computation platforms, without the risk of leaking the information about the data. It is also capable of encoding a vast amount of data effectively at a later time using classical computations, thus saving runtime on quantum computation devices. The trained quantum machine learning models can be run completely on classical computers, meaning the dataset owner does not need to have any quantum hardware, nor even quantum simulators. Moreover, our method mitigates the encoding bottleneck by reducing the required circuit depth from $O(2^{n})$ to $O(n)$, and relax the tolerance on the precision of the quantum gates for the encoding. These results demonstrate yet another advantage of quantum and quantum-inspired machine learning models over existing classical neural networks, and broaden the approaches to data security.

quant-ph↗

arXiv2023

Comment on "Masking quantum information is impossible"

The no-masking theorem (Phys. Rev. Lett. 120, 230501 (2018)) claims that arbitrary quantum states cannot be masked. Based on this result, the authors further suggested that qubit commitment is not possible. Here we show that this connection does not hold in general.

quant-ph↗

arXiv2023

Computing the gradients with respect to all parameters of a quantum neural network using a single circuit

Finding gradients is a crucial step in training machine learning models. For quantum neural networks, computing gradients using the parameter-shift rule requires calculating the cost function twice for each adjustable parameter in the network. When the total number of parameters is large, the quantum circuit must be repeatedly adjusted and executed, leading to significant computational overhead. Here we propose an approach to compute all gradients using a single circuit only, significantly reducing both the circuit depth and the number of classical registers required. We experimentally validate our approach on both quantum simulators and IBM's real quantum hardware, demonstrating that our method significantly reduces circuit compilation time compared to the conventional approach, resulting in a substantial speedup in total runtime.

quant-ph↗

arXiv2023

A no-go result on observing quantum superpositions

We give a general proof showing that once irreversible processes are involved, a class of projective measurements is impossible. Applying this no-go result to the Schroedinger's cat paradox implies that if something is claimed to be a real Schroedinger's cat, there will be no measurable difference between it and a trivial classical mixture of ordinary cats in any physically implementable process, otherwise raising the dead will become reality. Other similar macroscopic quantum superpositions cannot be observed either due to the lack of non-commuting measurement bases. Our proof does not involve any quantum interpretation theory and hypothesis.

quant-ph↗

arXiv2022

Collaboration between parallel connected neural networks -- A possible criterion for distinguishing artificial neural networks from natural organs

We find experimentally that when artificial neural networks are connected in parallel and trained together, they display the following properties. (i) When the parallel-connected neural network (PNN) is optimized, each sub-network in the connection is not optimized. (ii) The contribution of an inferior sub-network to the whole PNN can be on par with that of the superior sub-network. (iii) The PNN can output the correct result even when all sub-networks give incorrect results. These properties are unlikely for natural biological sense organs. Therefore, they could serve as a simple yet effective criterion for measuring the bionic level of neural networks. With this criterion, we further show that when serving as the activation function, the ReLU function can make an artificial neural network more bionic than the sigmoid and Tanh functions do.

cs.LG↗

arXiv2021

Measurement-device-independent quantum key distribution with classical Bob and no joint measurement

Measurement-device-independent quantum key distribution (MDI-QKD) provides a method for secret communication whose security does not rely on trusted measurement devices. In all existing MDI-QKD protocols, the participant Charlie has to perform the Bell state measurement or other joint measurements. Here we propose an MDI-QKD protocol which requires individual measurements only. Meanwhile, all operations of the receiver Bob are classical, without the need for preparing and measuring quantum systems. Thus the implementation of the protocol has a lower technical requirement on Bob and Charlie.

quant-ph↗

arXiv2020

Realizing the "fictitious" beam splitter -- A stationary implementation of semi-counterfactual interaction-free imaging

Based on quantum counterfactual interaction-free measurement, we propose an implementation scheme for a beam splitter with anomalous reflection and transmission properties that looks impossible at first glance. Our scheme is stationary without requiring switchable mirrors and polarization rotators. Using the scheme for imaging will ensure that the optical radiation received by the object being imaged can be arbitrarily low. Thus it enables applications such as stealthy night vision devices that can work without detectable ambient light, or being used as a hackware against some counterfactual quantum cryptographic protocols.

quant-ph↗

arXiv2019

An optical implementation of quantum bit commitment using infinite-dimensional systems

Unconditionally secure quantum bit commitment (QBC) was widely believed to be impossible for more than two decades. But recently, based on an anomalous behavior found in quantum steering, we proposed a QBC protocol which can be unconditionally secure in principle. The protocol requires the use of infinite-dimensional systems, therefore it may seem less feasible in practice. Here we propose a quantum optical method based on Mach-Zehnder interferometer, which gives a very good approximation to such infinite-dimensional systems. Thus, it enables a proof-of-principle experimental implementation of our protocol, which can also serve as a practically secure QBC scheme. Other multi-party cryptographic protocols such as quantum coin tossing can be built upon it too. Our approach also reveals a relationship between infinity and non-locality, which may have an impact on the research of fundamental theories.

quant-ph↗

arXiv2019

Cryptanalysis and improvement of Wu-Cai-Wu-Zhang's quantum private comparison protocol

In a recent paper (Int. J. Quantum Inf. 17 (2019) 1950026), the authors discussed the shortcomings in the security of a quantum private comparison protocol that we previously proposed (Int. J. Quantum Inf. 15 (2017) 1750014). They also proposed a new protocol aimed to avoid these problems. Here we analysis the information leaked in their protocol, and find that it is even less secure than our protocol in certain cases. We further propose an improved version which has the following advantages: (1) no entanglement needed, (2) quantum memory is no longer required, and (3) less information leaked. Therefore, better security and great feasibility are both achieved.

quant-ph↗

arXiv2018

Copenhagen interpretation can survive the upgraded Schroedinger's cat Gedankenexperiment

Recently, Frauchiger and Renner proposed a Gedankenexperiment, which was claimed to be able to prove that quantum theory cannot consistently describe the use of itself. Here we show that the conclusions of Frauchiger and Renner actually came from their incorrect description of some quantum states. With the correct description there will be no inconsistent results, no matter which quantum interpretation theory is used. Especially, the Copenhagen interpretation can satisfy all the three assumptions (C), (Q), and (S) of Frauchiger and Renner simultaneously, thus it has no problem consistently describing the use of itself.

quant-ph↗

arXiv2018

Practical quantum oblivious transfer with a single photon

Quantum oblivious transfer (QOT) is an essential cryptographic primitive. But unconditionally secure QOT is known to be impossible. Here we propose a practical QOT protocol, which is perfectly secure against dishonest sender without relying on any technological assumption. Meanwhile, it is also secure against dishonest receiver in the absence of long-term quantum memory and complicated collective measurements. The protocol is extremely feasible, as it can be implemented using currently available Mach-Zehnder interferometer, and no quantum memory, collective measurements nor entanglement are needed for honest participants. More importantly, comparing with other practical QOT schemes, our protocol has an unbeatable efficiency since it requires the transmission of a single photon only.

quant-ph↗

arXiv2017

Device-independent quantum private comparison protocol without a third party

Since unconditionally secure quantum two-party computations are known to be impossible, most existing quantum private comparison (QPC) protocols adopted a third party. Recently, we proposed a QPC protocol which involves two parties only, and showed that although it is not unconditionally secure, it only leaks an extremely small amount of information to the other party. Here we further propose the device-independent version of the protocol, so that it can be more convenient and dependable in practical applications.

quant-ph↗

arXiv2017

Unconditionally secure quantum bit commitment based on the uncertainty principle

Unconditionally secure quantum bit commitment (QBC) was considered impossible. But the no-go proofs are based on the Hughston-Jozsa-Wootters (HJW) theorem (a.k.a. the Uhlmann theorem). Recently it was found that in high-dimensional systems, there exist some states which can display a chaos effect in quantum steering, so that the attack strategy based on the HJW theorem has to require the capability of discriminating quantum states with very subtle difference, to the extent that is not allowed by the uncertainty principle. With the help of this finding, here we propose a simple QBC protocol which manages to evade the no-go proofs.

quant-ph↗

arXiv2017

Chaos in quantum steering in high-dimensional systems

Quantum steering means that in some bipartite quantum systems, the local measurements on one side can determine the state of the other side. Here we show that in high-dimensional systems, there exists a specific entangled state which can display a kind of chaos effect when being adopted for steering. That is, a subtle difference in the measurement results on one side can steer the other side into completely orthogonal states. Moreover, by expanding the result to infinite-dimensional systems, we find two sets of states for which, contrary to common belief, even though their density matrices approach being identical, the steering between them is impossible. This property makes them very useful for quantum cryptography.

quant-ph↗

arXiv2016

Quantum private comparison protocol without a third party

To evade the well-known impossibility of unconditionally secure quantum two-party computations, previous quantum private comparison protocols have to adopt a third party. Here we study how far we can go with two parties only. We propose a very feasible and efficient protocol. Intriguingly, although the average amount of information leaked cannot be made arbitrarily small, we find that it never exceeds 14 bits for any length of the bit-string being compared.

quant-ph↗

arXiv2016

Unconditionally secure quantum coin flipping

Quantum coin flipping (QCF) is an essential primitive for quantum cryptography. Unconditionally secure strong QCF with an arbitrarily small bias was widely believed to be impossible. But basing on a problem which cannot be solved without quantum algorithm, here we propose such a QCF protocol, and show how it manages to evade all existing no-go proofs on QCF.

quant-ph↗