Progressing of Quantum Tomography for Quantum Information Acquisition

In this paper we review a number of recent developments in the study of quantum tomography which is one of the useful methods for quantum state estimation and quantum information acquisition, having sparked explosion of interest in recent years. The quantum process tomography is also analyzed. At the same time, some success experiments and applications of quantum tomography are introduced. Finally, a number of open problems and future directions in this field are proposed.

Erratum to:Holocene temperature variation recorded by branched glycerol dialkyl glycerol tetraethers in a loess-paleosol sequence from the north-eastern Tibetan Plateau

Erratum to:Front.Earth Sci.DOI 10.1007/s11707-023-1094-6 The original version of this article unfortunately contained a mistake.The presentation of was incorrect.The corrected figure is given below.

Multi-step evolution and measurement control of finite-dimensional quantum systems

For finite-dimensional quantum systems,we propose a quantum control scheme based on a multi-step unitary evolution and quantum projective measurements.The objective is to design a control law to steer the system to a target eigenstate of the measurement operator in the least number of steps.Within each control step,unitary evolution and quantum projective measurement are performed in turn until the system reaches the target state.The control process can be modeled as a finite-state Markov chain with an absorbing state.We prove that the controlled system will converge to the target eigenstate with probability one after a finite number of control steps and find a minimal-step-number condition that would steer the system to the target eigenstate in the least number of steps.

Holocene temperature variation recorded by branched glycerol dialkyl glycerol tetraethers in a loess-paleosol sequence from the north-eastern Tibetan Plateau

Reconstructing Holocene temperature evolution is important for understanding present temperature variations and for predicting future climate change,in the context of global warming.The evolution of Holocene global temperature remains disputed,due to differences between proxy reconstructions and model simulations,a discrepancy known as the῾Holocene temperature conundrum᾽.More reliable and quantitative terrestrial temperature records are needed to resolve the spatial heterogeneity of existing records.In this study,based on the analysis of branched glycerol dialkyl glycerol tetraethers(brGDGTs)from a loess-paleosol sequence from the Ganjia Basin in the north-eastern Tibetan Plateau(NETP),we quantitatively reconstructed the mean annual air temperature(MAAT)over the past 12 ka.The MAAT reconstruction shows that the temperature remained low during the early Holocene(12−8 ka),followed by a rapid warming at around 8 ka.From 8 to 4 ka,the MAAT record reached its highest level,followed by a cooling trend from the late Holocene(4−0 ka).The variability of the reconstructed MAAT is consistent with trends of annual temperature records from the Tibetan Plateau(TP)during the Holocene.We attribute the relatively low temperatures during the early Holocene to the existence of ice sheets at high-latitude regions in the Northern Hemisphere and the weaker annual mean insolation at 35°N.During the mid to late Holocene,the long-term cooling trend in the annual temperature record was primarily driven by declining summer insolation.This study provides key geological evidence for clarifying Holocene temperature change in the TP.