Tailoring many-body interactions among a proper quantum system endows it with computing ability by means of static quantum computation in the sense that some of the physical degrees of freedom can be used to store binary information and the corresponding binary variables satisfy some given logic relations if and only if the system is in the ground state. Two theorems are proved showing that the universal static quantum computer can encode the solutions for any P and NP problem into its ground state using only polynomial number (in the problem input size) of logic gates. The second step is to read out the solutions by relaxing the system. The time complexity is relevant when one tries to read out the solution by relaxing the system, therefore our model of static quantum computation provides a new connection between the computational complexity and the dynamics of a complex system.
We first investigate the one-shot static entanglement cost to simulate a bipartite quantum channel under the set of non-entangling channels. The lower bound on the static entanglement cost is given by the generalized robustness of the target channel as well as the robust-generating power of the channel, which implies that the cost necessary to generate a bipartite quantum channel might not be retrievable in general. Next, we conceive a set of quantum channels that extends the set of non-entangling channels. We find out that the one-shot static entanglement cost under the extended set of channe…
Recent theoretical and experimental studies in quantum heat engines show that, in the quasi-static regime, it is possible to have higher efficiency than the limit imposed by Carnot, provided that engineered reservoirs are used. The quasi-static regime, however, is a strong limitation to the operation of heat engines, since infinitely long time is required to complete a cycle. In this paper we propose a two-level model as the working substance to perform a quantum Otto heat engine surrounded by a cold thermal reservoir and a squeezed hot thermal reservoir. Taking advantage of this model we show…
Influence of Noninertial Dynamics on Static Quantum Resource Theories
Sri Sai Ram Engineering College（斯里赛拉姆工程学院）；New York University Shanghai, NYU- ECNU Institute of Physics at NYU Shanghai（纽约大学上海分校，纽约大学上海NYU-华东师范大学物理研究所）；East China Normal University（华东师范大学）；NYUAD Research Institute, New York University Abu Dhabi（阿布扎比纽约大学研究院）；New York University（纽约大学）
Developing scalable quantum algorithms to study finite-temperature physics of quantum many-body systems has attracted considerable interest due to recent advancements in quantum hardware. However, such algorithms in their present form require resources that exceed the capabilities of current quantum computers except for a limited range of system sizes and observables. Here, we report calculations of finite-temperature properties including energies, static and dynamical correlation functions, and excitation spectra of spin Hamiltonians with up to four sites on five-qubit IBM Quantum devices. Th…
所谓的\emph{quantum game theory}是近年来量子信息理论和博弈论发展的新分支之一。然而，量子博弈本身的概念从未被严格定义，这导致了不同作者之间的许多概念混淆。在本文中，我们介绍了一个新的概念框架的\emph{scenario}和一个\emph{implementation}的游戏。它表明，在文献中提出的游戏的“量化”的程序，实际上导致几个不同的游戏，可以定义在同一个场景中，但除此之外，他们可能没有什么共同点与原来的游戏。在我们提出的框架内，围绕“量子博弈”产生的许多概念误解都可以得到明确的陈述和独特的解决。特别是，在几个静态的"量子游戏"，以及它们与贝尔不等式的连接，宣称的纠缠的重要作用，被推翻。
The basic Lipkin-Meshkov-Glick model displays a second order ground state quantum phase transition and an excited state quantum phase transition (ESQPT). The inclusion of an anharmonic term in the Hamiltonian implies a second ESQPT of a different nature. We characterize this ESQPT using the mean field limit of the model. The new ESQPT, associated with the changes in the boundary of the finite Hilbert space of the system, can be properly described using the order parameter of the ground state quantum phase transition, the energy gap between adjacent states, the participation ratio, and the quan…
Overcoming the Quasi-Static Bottleneck: A Finite-Time Quantum Otto Information Engine Achieving Near-Unity Efficiency
College of Physics, Jilin University（吉林大学物理学院）；Department of Chemistry and Department of Physics and Astronomy, State University of New York at Stony Brook（纽约州立大学石溪分校化学系和物理与天文学系）
The scalability of photonic implementations of fault-tolerant quantum computing based on Gottesman-Kitaev-Preskill (GKP) qubits is injured by the requirements of inline squeezing and reconfigurability of the linear optical network. In this work we propose a topologically error-corrected architecture that does away with these elements at no cost - in fact, at an advantage - to state preparation overheads. Our computer consists of three modules: a 2D array of probabilistic sources of GKP states; a depth-four circuit of static beamsplitters, phase shifters, and single-time-step delay lines; and a…
We present a protocol to achieve double quantum magnetometry at large static magnetic fields. This is a regime where sensitive sample parameters, such as the chemical shift, get enhanced facilitating their characterization. In particular, our method delivers two-tone stroboscopic radiation patterns with modulated Rabi frequencies to achieve larger spectral signals. Furthermore, it does not introduce inhomogeneous broadening in the sample spectrum preventing signal misinterpretation. Moreover, our protocol is designed to work under realistic conditions such as the presence of moderate microwave…
By means of quantum mechanics and quantum electrodynamics applied to coupled harmonic Drude oscillators, we study the interaction between two neutral atoms or molecules subject to a uniform static electric field. Our focus is to understand the interplay between leading contributions to field-induced electrostatics/polarization and dispersion interactions, as considered within the employed Drude model for both non-retarded and retarded regimes. For the first case, we present an exact solution for two coupled oscillators obtained by diagonalizing the corresponding quantum-mechanical Hamiltonian …
Quantum coherences are paramount resources for applications, such as quantum-enhanced light-harvesting or quantum computing, which are fragile against environmental noise. We here derive generalized quantum master equations using perturbation theory in order to describe the effective ensemble-averaged time-evolution of finite-size quantum systems subject to static noise on all time scales. We then analyse the time-evolution of the coherences under energy broadening noise in a variety of systems characterized by both short and long-range interactions, by strongly correlated and fully uncorrelat…
