| 1. |
|
|
| 2. |
- Annby-Andersson, Björn, et al.
(författare)
-
Maxwell's demon in a double quantum dot with continuous charge detection
- 2020
-
Ingår i: Physical Review B. - 2469-9950. ; 101:16
-
Tidskriftsartikel (refereegranskat)abstract
- Converting information into work has, during the past decade, gained renewed interest as it gives insight into the relation between information theory and thermodynamics. Here, we theoretically investigate an implementation of Maxwell's demon in a double quantum dot and demonstrate how heat can be converted into work using only information. This is accomplished by continuously monitoring the charge state of the quantum dots and transferring electrons against a voltage bias using a feedback scheme. We investigate the electrical work produced by the demon and find a non-Gaussian work distribution. To illustrate the effect of a realistic charge detection scheme, we develop a model taking into account noise as well as a finite delay time and show that an experimental realization is feasible with present day technology. Depending on the accuracy of the measurement, the system is operated as an implementation of Maxwell's demon or a single-electron pump.
|
|
| 3. |
- Annby-Andersson, Björn, et al.
(författare)
-
Quantum Fokker-Planck Master Equation for Continuous Feedback Control
- 2022
-
Ingår i: Physical Review Letters. - 0031-9007. ; 129:5
-
Tidskriftsartikel (refereegranskat)abstract
- Measurement and feedback control are essential features of quantum science, with applications ranging from quantum technology protocols to information-to-work conversion in quantum thermodynamics. Theoretical descriptions of feedback control are typically given in terms of stochastic equations requiring numerical solutions, or are limited to linear feedback protocols. Here we present a formalism for continuous quantum measurement and feedback, both linear and nonlinear. Our main result is a quantum Fokker-Planck master equation describing the joint dynamics of a quantum system and a detector with finite bandwidth. For fast measurements, we derive a Markovian master equation for the system alone, amenable to analytical treatment. We illustrate our formalism by investigating two basic information engines, one quantum and one classical.
|
|
| 4. |
|
|
| 5. |
- Gaillard, Marie-José, et al.
(författare)
-
Causes of Regional Change : Land Cover
- 2015
-
Ingår i: Second Assessment of Climate Change for the Baltic Sea Basin. - Cham : Springer. - 9783319160054 - 9783319160061 ; , s. 453-477
-
Bokkapitel (refereegranskat)abstract
- Anthropogenic land-cover change (ALCC) is one of the few climate forcings for which the net direction of the climate response over the last two centuries is still not known. The uncertainty is due to the often counteracting temperature responses to the many biogeophysical effects and to the biogeochemical versus biogeophysical effects. Palaeoecological studies show that the major transformation of the landscape by anthropogenic activities in the southern zone of the Baltic Sea basin occurred between 6000 and 3000/2500 cal year BP. The only modelling study of the biogeophysical effects of past ALCCs on regional climate in north-western Europe suggests that deforestation between 6000 and 200 cal year BP may have caused significant change in winter and summer temperature. There is no indication that deforestation in the Baltic Sea area since AD 1850 would have been a major cause of the recent climate warming in the region through a positive biogeochemical feedback. Several model studies suggest that boreal reforestation might not be an effective climate warming mitigation tool as it might lead to increased warming through biogeophysical processes.
|
|
| 6. |
- Gaillard, Marie-José, et al.
(författare)
-
Has anthropogenic land-cover change been a significant climate forcing in the past? : An assessment for the Baltic Sea catchment area based on a literature review
- 2015
-
Ingår i: Geophysical Research Abstracts.
-
Konferensbidrag (refereegranskat)abstract
- We reviewed the recent published scientific literature on land cover-climate interactions at the global and regional spatial scales with the aim to assess whether it is convincingly demonstrated that anthropogenic land-cover change (ALCC) has been (over the last centuries and millennia) a significant climate forcing at the global scale, and more specifically at the scale of the Baltic Sea catchment area. The conclusions from this review are as follows: i) anthropogenic land-cover change (ALCC) is one of the few climate forcings for which the net direction of the climate response in the past is still not known. The uncertainty is due to the often counteracting temperature responses to the many biogeophysical effects, and to the biogeochemical vs biogeophysical effects; ii) there is no indication that deforestation in the Baltic Sea area since AD 1850 would have been a major cause of the recent climate warming in the region through a positive biogeochemical feedback; iii) several model studies suggest that boreal reforestation might not be an effective climate warming mitigation tool as it might lead to increased warming through biogeophysical processes; iv) palaeoecological studies indicate a major transformation of the landscape by anthropogenic activities in the southern zone of the study region occurring between 6000 and 3000/2500 calendar years before present (cal. BP) (1) ; v) the only modelling study so far of the biogeophysical effects of past ALCCs on regional climate in Europe suggests that a deforestation of the magnitude of that reconstructed for the past (between 6000 and 200 cal BP) can produce changes in winter and summer temperatures of +/- 1, the sign of the change depending on the season and the region (2). Thus, if ALCC and their biogeophysical effects did matter in the past, they should matter today and in the future. A still prevailing idea is that planting trees will mitigate climate warming through biogeochemical effects. Therefore, there is still an urgent need to better understand the biogeophysical effects on regional and continental climate of afforestation in the hemiboreal and boreal regions, and their significance in relation to the biogeochemical effects.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Haldar, Subhomoy, et al.
(författare)
-
Microwave power harvesting using resonator-coupled double quantum dot photodiode
- 2024
-
Ingår i: Physical Review B. - 2469-9950. ; 109:8
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a microwave power-to-electrical energy conversion in a resonator-coupled double quantum dot. The system, operated as a photodiode, converts individual microwave photons to electrons tunneling through the double dot, resulting in an electrical current flowing against the applied voltage bias at input powers down to 1 fW. The device attains a maximum power harvesting efficiency of 2%, with the photon-to-electron conversion efficiency reaching 12% in the single-photon absorption regime. We find that the power conversion depends on thermal effects showing that thermodynamics plays a crucial role in the single-photon energy conversion.
|
|
| 10. |
- Kerremans, Timo, et al.
(författare)
-
Probabilistically violating the first law of thermodynamics in a quantum heat engine
- 2022
-
Ingår i: SciPost Physics. - 2542-4653. ; 12:5
-
Tidskriftsartikel (refereegranskat)abstract
- Fluctuations of thermodynamic observables, such as heat and work, contain relevant information on the underlying physical process. These fluctuations are however not taken into account in the traditional laws of thermodynamics. While the second law is extended to fluctuating systems by the celebrated fluctuation theorems, the first law is generally believed to hold even in the presence of fluctuations. Here we show that in the presence of quantum fluctuations, also the first law of thermodynamics may break down. This happens because quantum mechanics imposes constraints on the knowledge of heat and work. To illustrate our results, we provide a detailed case-study of work and heat fluctuations in a quantum heat engine based on a circuit QED architecture. We find probabilistic violations of the first law and show that they are closely connected to quantum signatures related to negative quasi-probabilities. Our results imply that in the presence of quantum fluctuations, the first law of thermodynamics may not be applicable to individual experimental runs.
|
|
