Zobrazeno 1 - 10
of 24
pro vyhledávání: '"Hörnedal, Niklas"'
Non-Hermitian dynamics in quantum systems preserves the rank of the state density operator. We use this insight to develop its geometrical description. In particular, we identify mutually orthogonal coherent and incoherent directions and give their p
Externí odkaz:
http://arxiv.org/abs/2405.13913
Autor:
Hörnedal, Niklas, Sönnerborn, Ole
Publikováno v:
Phys. Scr. 98, 105108 (2023)
Geometric phase is a concept of central importance in virtually every branch of physics. In this paper, we show that the evolution time of a cyclically evolving quantum system is restricted by the system's energy resources and the geometric phase acq
Externí odkaz:
http://arxiv.org/abs/2305.12156
Autor:
Hörnedal, Niklas, Sönnerborn, Ole
Publikováno v:
Phys. Rev. A 108, 052421 (2023)
Many quantum speed limits for isolated systems can be generalized to also apply to closed systems. This is, for example, the case with the well-known Mandelstam-Tamm quantum speed limit. Margolus and Levitin derived an equally well-known and ostensib
Externí odkaz:
http://arxiv.org/abs/2303.09423
Autor:
Hörnedal, Niklas, Sönnerborn, Ole
Publikováno v:
Phys. Rev. Res. 5, 043234 (2023)
The Mandelstam-Tamm and Margolus-Levitin quantum speed limits are two well-known evolution time estimates for isolated quantum systems. These bounds are usually formulated for fully distinguishable initial and final states, but both have tight extens
Externí odkaz:
http://arxiv.org/abs/2301.10063
Publikováno v:
Quantum 7, 1055 (2023)
Quantum speed limits (QSLs) provide lower bounds on the minimum time required for a process to unfold by using a distance between quantum states and identifying the speed of evolution or an upper bound to it. We introduce a generalization of QSL to c
Externí odkaz:
http://arxiv.org/abs/2301.04372
Publikováno v:
Quantum 6, 884 (2022)
Quantum speed limits (QSLs) identify fundamental time scales of physical processes by providing lower bounds on the rate of change of a quantum state or the expectation value of an observable. We introduce a generalization of QSL for unitary operator
Externí odkaz:
http://arxiv.org/abs/2207.05769
Publikováno v:
Commun. Phys. 5, 207 (2022)
In an isolated system, the time evolution of a given observable in the Heisenberg picture can be efficiently represented in Krylov space. In this representation, an initial operator becomes increasingly complex as time goes by, a feature that can be
Externí odkaz:
http://arxiv.org/abs/2202.05006
Autor:
Hörnedal, Niklas
Quantum speed limits are lower bounds on the evolution time for quantum systems. In this thesis, we consider closed quantum systems. We investigate how different principal bundles offers a geometrical method for obtaining generalizations of the Mande
Externí odkaz:
http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-193265
Publikováno v:
New J. Phys. 24 (2022) 055004
The Mandelstam-Tamm quantum speed limit puts a bound on how fast a closed system in a pure state can evolve. In this paper, we derive several extensions of this quantum speed limit to closed systems in mixed states. We also compare the strengths of t
Externí odkaz:
http://arxiv.org/abs/2112.08017
Publikováno v:
Quantum 5, 462 (2021)
In this paper, we derive sharp lower bounds, also known as quantum speed limits, for the time it takes to transform a quantum system into a state such that an observable assumes its lowest average value. We assume that the system is initially in an i
Externí odkaz:
http://arxiv.org/abs/2011.11963