
Ville Maisi
Assistant Professor, Coordinator Quantum Physics

Research:
My research interests lies in single-electron devices where the movement of individual electrons is controlled. On one hand, our research of these devices aims to develop applications such as thermometers, quantized electrical current sources and qubits for quantum computing. On the other hand, these devices suit ideally for addressing fundamental physics questions because their operation is based on quantum mechanics. In addition, these nanometer-sized devices are so small that fluctuations in them play an important role. This opens up an excellent opportunity to study fluctuations and non-equilibrium thermodynamics experimentally. The nanothermodynamics of the small systems has become an active field of paramount importance in recent years as the size of electronic devices continue to shrink towards the atomic scale.
Our experience covers both metallic and semiconducting single-electron devices. One of the main experimental techniques utilized is real-time charge detection that is illustrated in Fig. 1 and 2 below. Figure 1 shows the a real-time detection of spin flips in semiconductor quantum dots. The device, shown in panel (a), consists of two dots holding two electrons that are indicated with the arrows. We utilize a nearby quantum point contact (QPC) to measure whether the electrons are residing on separate dots, in state (1,1), or in the same dot, in state (2,0). Panel (b) shows the measured current thought the QPC as a function of time. Electron tunneling results in switching between the two states. If the electrons have spins in parallel direction, the system stays a long time in the (1,1) state and no tunneling occurs due to Pauli exclusion principle. Once the spin flips, the tunneling becomes possible resulting in a burst of tunneling events until blockade occurs again. The beginning and the end of such burst pinpoints the spin flipping events in our system.
Fig. 1. Real-time detection of spin blockade in a double quantum dot. Figure adapted from Phys. Rev. Lett. 116, 136803 (2016).
Figure 2 shows another example on the field of nanothermodynamics with a metallic device. We demonstrated the fundamental relation between information and physical work. Our device holds one bit of information in form of an electron that can reside either on left or right metallic island. Panel (a) shows an energy diagram and (b) the actual device with blue circles denoting the possible locations of the electron. By applying a fast pulse locking the electron to one island followed by a slow adiabatic drive back to the original state with equal probability for the electron to reside in either of the islands, we converted information into useful work W. Our system performed this conversion close to the fundamental limit of W = kT ln(2), which is the inverse cycle of the renown Landauer's principle. Fig. 2 (c) shows typical example traces of the information-to-energy conversion cycles.
Fig. 2. Information-to-energy conversion close to the Landauer limit. Figure adapted from PNAS 111, 13786 (2014).
Currently my research focuses on studying quantum dots in InAs nanowires. As one-dimensional structures with strong spin-orbit interactions, they form an interesting host material for example for studying spin physics, electron-phonon interactions in reduced dimensionality as well as Majorana states that are foreseen as the building blocks of topologically protected quantum computing.
Publications
Displaying of publications. Sorted by year, then title.
Minimally Dissipative Information Erasure in a Quantum Dot via Thermodynamic Length
Matteo Scandi, David Barker, Sebastian Lehmann, Kimberly A. Dick, Ville F. Maisi, et al.
(2022) Physical Review Letters, 129
Journal articleLocal and Nonlocal Two-Electron Tunneling Processes in a Cooper Pair Splitter
Antti Ranni, Elsa T. Mannila, Axel Eriksson, Dmitry S. Golubev, Jukka P. Pekola, et al.
(2022) Physical Review Letters, 129
Journal articleExperimental Verification of the Work Fluctuation-Dissipation Relation for Information-to-Work Conversion
David Barker, Matteo Scandi, Sebastian Lehmann, Claes Thelander, Kimberly A. Dick, et al.
(2022) Physical Review Letters, 128
Journal articleQuantum Confinement Suppressing Electronic Heat Flow below the Wiedemann–Franz Law
Danial Majidi, Martin Josefsson, Mukesh Kumar, Martin Leijnse, Lars Samuelson, et al.
(2022) Nano Letters, 22 p.630-635
Journal articleA superconductor free of quasiparticles for seconds
E. T. Mannila, P. Samuelsson, S. Simbierowicz, J. T. Peltonen, V. Vesterinen, et al.
(2021) Nature Physics
Journal articleEfficient and continuous microwave photoconversion in hybrid cavity-semiconductor nanowire double quantum dot diodes
Waqar Khan, Patrick P. Potts, Sebastian Lehmann, Claes Thelander, Kimberly A. Dick, et al.
(2021) Nature Communications, 12
Journal articleReal-time observation of Cooper pair splitting showing strong non-local correlations
Antti Ranni, Fredrik Brange, Elsa T. Mannila, Christian Flindt, Ville F. Maisi
(2021) Nature Communications, 12
Journal articleSelf-Calibrating Superconducting Pair-Breaking Detector
E. T. Mannila, V. F. Maisi, J. P. Pekola
(2021) Physical Review Letters, 127
Journal articlePhonon spectral density in a GaAs/AlGaAs double quantum dot
A. Hofmann, C. Karlewski, A. Heimes, C. Reichl, W. Wegscheider, et al.
(2020) Physical Review Research, 2
Journal articleMaxwell's demon in a double quantum dot with continuous charge detection
Björn Annby-Andersson, Peter Samuelsson, Ville F. Maisi, Patrick P. Potts
(2020) Physical Review B, 101
Journal articleAmbipolar transport in narrow bandgap semiconductor InSb nanowires
B. Dalelkhan, D. J.O. Göransson, C. Thelander, K. Li, Y. J. Xing, et al.
(2020) Nanoscale, 12 p.8159-8165
Journal articleCoulomb blockade from the shell of an InP-InAs core-shell nanowire with a triangular cross section
D. J.O. Göransson, M. Heurlin, B. Dalelkhan, S. Abay, M. E. Messing, et al.
(2019) Applied Physics Letters, 114
Journal articleExtreme reductions of entropy in an electronic double dot
Shilpi Singh, Édgar Roldán, Izaak Neri, Ivan M. Khaymovich, Dmitry S. Golubev, et al.
(2019) Physical Review B, 99
Journal articleDetecting parity effect in a superconducting device in the presence of parity switches
E. T. Mannila, V. F. Maisi, H. Q. Nguyen, C. M. Marcus, J. P. Pekola
(2019) Physical Review B, 100
Journal articleIndividually addressable double quantum dots formed with nanowire polytypes and identified by epitaxial markers
D. Barker, S. Lehmann, L. Namazi, M. Nilsson, C. Thelander, et al.
(2019) Applied Physics Letters, 114
Journal article