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Adiabatic quantum computation employs a slow change of a time-dependent control function (or functions) to interpolate between an initial and final Hamiltonian, which helps to keep the system in the instantaneous ground state. When the…

Quantum Physics · Physics 2014-06-26 Constantin Brif , Matthew D. Grace , Mohan Sarovar , Kevin C. Young

Extending notions of phase transitions to nonequilibrium realm is a fundamental problem for statistical mechanics. While it was discovered that critical transitions occur even for transient states before relaxation as the singularity of a…

Statistical Mechanics · Physics 2021-09-02 Ryusuke Hamazaki

Nonequilibrium states of closed quantum many-body systems defy a thermodynamic description. As a consequence, constraints such as the principle of equal a priori probabilities in the microcanonical ensemble can be relaxed, which can lead to…

Statistical Mechanics · Physics 2019-03-27 Markus Heyl

The speed limit provides an upper bound for the dynamical evolution time of a quantum system. Here, we introduce the notion of quantum acceleration limit for unitary time evolution of quantum systems under time-dependent Hamiltonian. We…

Quantum Physics · Physics 2023-12-20 Arun Kumar Pati

We extend the concept of quantum speed limit -- the minimal time needed to perform a driven evolution -- to complex interacting many-body systems. We investigate a prototypical many-body system, a bosonic Josephson junction, at increasing…

The phase shift rules enable the estimation of the derivative of a quantum state with respect to phase parameters, providing valuable insights into the behavior and dynamics of quantum systems. This capability is essential in quantum…

Quantum Physics · Physics 2023-09-15 L. A. Markovich , S. Malikis , S. Polla , J. T. Brugués

When a quantum system undergoes unitary evolution in accordance with a prescribed Hamiltonian, there is a class of states |psi> such that, after the passage of a certain time, |psi> is transformed into a state orthogonal to itself. The…

Quantum Physics · Physics 2009-11-10 Dorje C. Brody

While there are various approaches to benchmark physical processors, recent findings have focused on computational phase transitions. This is due to several factors. Importantly, the hardest instances appear to be well-concentrated in a…

Quantum Physics · Physics 2021-04-08 Hariphan Philathong , Vishwa Akshay , Ksenia Samburskaya , Jacob Biamonte

We show that optimizing a quantum gate for an open quantum system requires the time evolution of only three states irrespective of the dimension of Hilbert space. This represents a significant reduction in computational resources compared…

Quantum Physics · Physics 2021-02-16 Michael H. Goerz , Daniel M. Reich , Christiane P. Koch

We obtain exact solutions of the (2+1) dimensional Dirac oscillator in a homogeneous magnetic field within a minimal length ($\Delta x_0=\hbar \sqrt{\beta}$), or generalised uncertainty principle (GUP) scenario. This system in ordinary…

Quantum Physics · Physics 2015-06-23 L. Menculini , O. Panella , P. Roy

We study decoherence induced by a dynamic environment undergoing a quantum phase transition. Environment's susceptibility to perturbations - and, consequently, efficiency of decoherence - is amplified near a critical point. Over and above…

Quantum Physics · Physics 2013-05-29 Bogdan Damski , H. T. Quan , Wojciech H. Zurek

The ability to characterise a Hamiltonian with high precision is crucial for the implementation of quantum technologies. In addition to the well-developed approaches utilising optimal probe states and optimal measurements, the method of…

Quantum Physics · Physics 2022-12-14 Shushen Qin , Marcus Cramer , Christiane P. Koch , Alessio Serafini

Bounds of the minimum evolution time between two distinguishable states of a system can help to assess the maximal speed of quantum computers and communication channels. We study the quantum speed limit time of a composite quantum states in…

Quantum Physics · Physics 2014-09-16 Ying-Jie Zhang , Wei Han , Yun-Jie Xia , Ke-Xia Jiang , Jun-Peng Cao , Heng Fan

Non-classical features of quantum systems can degrade when subjected to environment and noise. Here, we ask a fundamental question: What is the minimum amount of time it takes for a quantum system to exhibit non-classical features in the…

Quantum Physics · Physics 2024-09-23 Divyansh Shrimali , Swapnil Bhowmick , Arun Kumar Pati

Bounds to the speed of evolution of a quantum system are of fundamental interest in quantum metrology, quantum chemical dynamics and quantum computation. We derive a time-energy uncertainty relation for open quantum systems undergoing a…

Quantum Physics · Physics 2013-03-05 A. del Campo , I. L. Egusquiza , M. B. Plenio , S. F. Huelga

We show that a closed quantum system driven through a quantum critical point with two rates $\omega_1$ (which controls its proximity to the quantum critical point) and $\omega_2$ (which controls the dispersion of the low-energy…

Quantum Gases · Physics 2014-10-01 Jay D. Sau , K. Sengupta

We study the minimum time related to the quantum speed limit that characterizes the evolution of an open quantum system with the help of a simple model in the short and long time limits. We compare in particular the situation corresponding…

Quantum Physics · Physics 2016-04-12 Jean Richert , Tarek Khalil

We study time-optimal protocols for controlling quantum systems which show several avoided level crossings in their energy spectrum. The structure of the spectrum allows us to generate a robust guess which is time-optimal at each crossing.…

Quantum Physics · Physics 2015-11-18 P. M. Poggi , F. C. Lombardo , D. A. Wisniacki

Tracking the time evolution of a quantum state allows one to verify the thermalization rate or the propagation speed of correlations in generic quantum systems. Inspired by the energy-time uncertainty principle, bounds have been…

Any physical system evolves at a finite speed that is constrained not only by the energetic cost but also by the topological structure of the underlying dynamics. In this Letter, by considering such structural information, we derive a…

Quantum Physics · Physics 2023-01-06 Tan Van Vu , Keiji Saito