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X

QCMX Lab

 

Team members

Faculty

Landry BRETHEAU
Assistant Professor
landry.bretheau[at]polytechnique.edu
Phone: +33169334477
Building 83, Room 83-20-20

Jean-Damien PILLET
Assistant Professor
jean-damien.pillet[at]polytechnique.edu
Phone: +33169334476
Building 83, Room 83-20-20

Students and Postdocs

Ambroise PEUGEOT - Post-Doctoral Associate funded by ANR on the QIPHSC project.

Former interns

2020: Etienne BARGEL (ENS Paris-Saclay L3), Elie DE SEZE (ENS Paris-Saclay L3), Luke PILACHE (X-Bachelor L2).


News

  • Oct 2020: Welcome to Ambroise who joined the group as a post-doctoral associate.
  • Sep 2020: Congrats to JD who was awarded a young researcher grant from ANR.
  • Sep 2020: Landry was awarded an ERC Starting Grant!  → X news article
  • Jun 2020: Congrats to JD for his paper published in SciPost Physics Core on the Scattering description of Andreev molecules.
  • Jun 2020: Welcome to Etienne, Elie & Luke who joined the group as summer interns.
  • Mar 2020: Congrats to Landry who was awarded the 2020 Nicholas Kurti Science Prize, together with Rebeca Ribeiro from CNRS C2N à X news article
  • Feb 2020: Tons of room-T µwave components have arrived.
  • Nov 2019: Congrats to JD for his nice PRL paper that reports how a carbon nanotube can be used to guide electrons in graphene à spolight in Physics, Science & MRS Bulletin
  • Sep 2019: New DC electronic instruments (oscillos, sources, DAC, amp).
  • Sep 2019: JD and Landry got tenured!
  • Aug 2019: Congrats to JD for his paper published in Nano Letters on Nonlocal Josephson effect in Andreev molecules.
  • Aug 2019: New paper by JD & co published in Physical Review Applied on Injection Locking and Parametric Locking in a Superconducting Circuit.
  • Jul 2019: We've received our cryogenic circulators and amplifiers from LNF.
  • Apr 2019: We've installed our new BlueFors dilution refregirator. Base temp = 8 mK !!!
  • Mar 2019: After 3 months, electricity, masonry and plumbing works are finished! Our lab is ready to get the fridge. And we've just received our expresso machine !
  • Jan 2019: New RF equipments from Rohde & Schwarz (1 VNA, 1 PSA and 3 MSG).
  • Jan 2019: Congrats to Landry for his paper published in Nature Nanotechnology on a graphene-based superconducting qubit à spotlight by Nature Nano & MIT News
  • Nov 2018: New paper by Landry & co published in Science that shows gate-controllable superconductivity in monolayer WTe2 à spotlight by MIT News
  • Sep 2018: We've received a 40L cylinder of He3. Thanks to MHD and the DOE :)
  • Sep 2018: New paper by Landry & co in PRB that reports tunneling spectroscopy measurements of graphene proximitized by large-gap superconductors.
  • Jul 2018: Congrats to Landry who was awarded a young researcher grant from ANR.
  • Dec 2017: The QCMX-lab was awarded a grant from SIRTEQ.
  • Sep 2017: We've been hired as assistant professors (with startup grant and lab space). Let's build from scratch a new lab. Long-live QCMX!

Research

Strategy

The goal of the QCMX project is to explore the quantum properties of electronic circuits and matter. Our strategy consists in coupling superconducting circuits normally used to process quantum information to materials in order to probe their quantum properties and discover new electronic states of matter. This could make it possible to identify new carriers of quantum information and to simulate complex many-body quantum problems.

A laboratory dedicated to hybrid quantum circuits

The QCMX activity started in September 2017. Since then, a lab dedicated to the realization and measurement of hybrid quantum circuits has been built. This requires access to temperatures close to absolute zero (few mK), nanofabrication tools for the creation of new architectures and electronic instruments in the DC and microwave range for quantum control. The dilution cryostat (from the company BlueFors) was installed in the QCMX-lab in spring 2019, which makes it the coldest point of l'X. First measurements of quantum circuits have started in 2020.

One of the crucial ingredients for the operation of quantum circuits is the non-linearity provided by a non-dissipative electronic component called a Josephson junction. These junctions are usually made of two superconductors coupled by tunnel effect through a thin insulating barrier. There is however a wider class of Josephson junctions where superconductors are connected by quantum conductors, such as graphene, semiconductor nanowires or carbon nanotubes. In these systems, barely exploited in the context of quantum circuits, physics is richer because they host additional degrees of freedom associated with the electronic properties of quantum conductors.

The purpose of the QCMX project is to use this unexploited resource to design new quantum devices, notably through the development of ultra-clean growth of carbon nanotubes that can be integrated into superconducting circuits. Such Josephson junctions then host elementary electronic excitations in the GHz energy range that can be controlled coherently by means of microwave signals. Our circuits, placed in a microwave cavity to protect it from environmental decoherence, will allow to detect new electronic states of matter such as, for example, Andreev Bound States, Weyl fermions or Majorana fermions.

Quantum simulations

Hybrid quantum circuit architectures as developed within the QCMX activity offer tremendous opportunities for quantum simulation, particularly to answer modern questions of fundamental Physics.

For example, a charge trapped in a nanotube or a semiconducting nanowire, connected in parallel to a Josephson junction can simulate the problem of a spin 1/2 immersed in a space-dependent magnetic field. In the quantum regime, the degrees of freedom of spin and position are entangled and obey a joined dynamic of great complexity. This experiment would make it possible to understand in more details the spin-boson model which is at the heart of the description of the dissipation in quantum physics.

Beyond this basic situation, it is possible to imagine more complex systems based on networks of several quantum objects. For example, a carbon nanotube connected to multiple superconducting electrodes may behave as a network of quantum dots. Strategies to perform the quantum teleportation of an electron within such electronic device are currently developing .


Recruiting

We are always looking for highly motivated master students, PhD students or postdocs. Please contact us by email.


Teaching

Jean-Damien and Landry have each a 192 hour / year teaching service. They are teaching at the undergrad level in Quantum Mechanics (PHY 361) and Advanced Quantum Physics (PHY 430). Landry is also in charge of a research module on Quantum Technologies (PHY599). You'll find here a video of a broad audience Conference on Quantum Technologies that Landry gave to the X'19 together with Alain Aspect in April 2020.


Fundings

With the financial support of: