Lloyd has considered the ultimate limitations physics places on quantum computers. He concludes in particular that for an ``ultimate laptop'' (a computer of one liter of volume and one kilogram of mass) the maximum number of operations per second is bounded by $10^{51}$. The limit is derived considering ordinary quantum mechanics. Here we consider additional limits that are placed by quantum gravity ideas, namely the use of a relational notion of time and fundamental gravitational limits that exist on time measurements. We then particularize for the case of an ultimate laptop and show that the maximum number of operations is further constrained to $10^{47}$ per second.
Hybrid adiabatic quantum computing for tomographic image reconstruction -- opportunities and limitations
Friedrich-Alexander Universität Erlangen-Nürnberg（埃尔朗根-纽伦堡弗里德里希-亚历山大大学）；Siemens Healthineers GmbH（西门子医疗有限公司）；Siemens Medical Solutions USA, Inc（美国西门子医疗解决方案公司）
Autonomous Quantum Processing Unit: An Autonomous Thermal Computing Machine & its Physical Limitations
Atominstitut, TU Wien（维也纳工业大学原子研究所）；Vienna Center for Quantum Science and Technology, TU Wien（维也纳量子科学与技术中心）；Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences（奥地利科学院量子光学与量子信息研究所）
Reliable AI: Does the Next Generation Require Quantum Computing?
Ludwig-Maximilians-Universität München（慕尼黑大学）；Technical University of Munich（慕尼黑工业大学）；Munich Center for Quantum Science and Technology（慕尼黑量子科学与技术中心）；Munich Center for Machine Learning（慕尼黑机器学习中心）
