一个模拟非本地PR盒的真实设备，无需通信

Black-box quantum state preparation without arithmetic

Black-box quantum state preparation is an important subroutine in many quantum algorithms. The standard approach requires the quantum computer to do arithmetic, which is a key contributor to the complexity. Here we present a new algorithm that avoids arithmetic. We thereby reduce the number of gates by a factor of 286-374 over the best prior work for realistic precision; the improvement factor increases with the precision. As quantum state preparation is a crucial subroutine in many approaches to simulating physics on a quantum computer, our new method brings useful quantum simulation closer t…

Random access codes and non-local resources

It is known that a PR-BOX (PR), a non-local resource and $(2\rightarrow 1)$ random access code (RAC), a functionality (wherein Alice encodes 2 bits into 1 bit message and Bob learns one of randomly chosen Alice's inputs) are equivalent under the no-signaling condition. In this work we introduce generalizations to PR and $(2\rightarrow 1)$ RAC and study their inter-convertibility. We introduce generalizations based on the number of inputs provided to Alice, $B_n$-BOX and $(n\rightarrow 1)$ RAC. We show that a $B_n$-BOX is equivalent to a no-signaling $(n\rightarrow 1)$ RACBOX (RB). Further we i…

Building the Observer into the System: Toward a Realistic Description of Human Interaction with the World

Human beings do not observe the world from the outside, but rather are fully embedded in it. The sciences, however, often give the observer both a "god's eye" perspective and substantial a~priori knowledge. Motivated by W. Ross Ashby's statement, "the theory of the Black Box is merely the theory of real objects or systems, when close attention is given to the question, relating object and observer, about what information comes from the object, and how it is obtained" (Introduction to Cybernetics, 1956, p. 110), I develop here an alternate picture of the world as a black box to which the observ…

非局部盒复杂性与安全函数计算

Non-Local Box Complexity and Secure Function Evaluation

非本地盒是一种抽象设备，Alice和Bob分别向其中输入比特x和y，并分别接收输出a和b，其中a，b均匀分布，a+b的奇偶性等于xy。这种盒子一直是研究量子或广义非定域性以及模拟非信号分布的核心。在本文中，我们首先研究Alice和Bob需要多少个非局部盒子来计算布尔函数f。我们提供了严格的上限和下限方面的通信复杂性的函数在确定性和随机的情况下。然后，我们继续表明，非局部盒复杂性的研究有有趣的应用经典计算。特别是，我们看看安全的函数评估，并研究了Beimel和Malkin提出的问题，Alice和Bob需要多少不经意传输调用才能安全地计算函数f。我们证明了这个问题与函数的非局部盒复杂性有关，并通过大大提高它们的边界得出结论。最后，我们的结果的另一个结果是，最大纠缠态的无痕双结果测量可以用3个非局域盒来模拟，而以前没有有限的限制是已知的。

利用非信号量子资源对超量子非局域关联（例如 Popescu-Rohrlich 盒）进行光子模拟

Photonic Simulation of Beyond-Quantum Nonlocal Correlations (e.g. Popescu-Rohrlich Box) with Non-Signaling Quantum Resources

本文提出利用本质非信号的物理资源与系统间动力学关联模拟 Popescu-Rohrlich 等超量子非局域关联，并在四量子比特光子平台上验证。

No quantum realization of extremal no-signaling boxes

Pure states are very important in any theory since they represent states of maximal information about the system within the theory. Here, we show that no non-trivial (not local realistic) extremal states (boxes) of general no-signaling theories can be realized within quantum theory. We then explore three interesting consequences of this fact. Firstly, since the pure states are uncorrelated from the environment, the statement forms a no-go result against the most straightforward device-independent protocol for randomness or secure key generation against general no-signaling adversaries. It also…

Quantum particle in a split box: Excitations to the ground state

We discuss two different approaches for splitting the wavefunction of a single-particle-box (SPB) into two equal parts. Adiabatic insertion of a barrier in the center of a SPB in order to make two compartments which each have probability 1/2 to find the particle in it is one of the key steps for a Szilard engine. However, any asymmetry between the volume of the compartments due to an off-center insertion of the barrier results in a particle that is fully localized in the larger compartment, in the adiabatic limit. We show that rather than exactly splitting the eigenfunctions in half by a symme…