News items

6/25/24

NewScientist magazine has published a news article about our forthcoming article in Physical Review A, entitled" Super-phenomena for arbitrary quantum observables".  Thanks go to Karmela Padavic-Callaghan for writing the article.

Update: 7/11/2024:  The article is published in Physical Review A.

6/25/24

Congratulations go to Tathagata Karmakar for the successful defense of his PhD thesis, entitled “System Characterization and Optimality in Quantum and Classical Technologies".

3/20/24

Student journalist Dimitra Manatou has published the article:

UNLOCKING THE QUANTUM REALM: INSIGHTS AND INNOVATIONS FROM THE THINKING BEYOND WEBINAR

in the Arizona State Press.  It is a great article about my recent interview and discussion on the "Thinking Beyond" podcast, with Paul Davies. 

2/15/24

I’m delighted to announce that my book, Quantum Measurement: Theory and Practice, is published today. Copies can be purchased (and previewed) at this link.

My coauthor is Irfan Siddiqi (UC Berkeley).

2/13/24

Cambridge University Press has published a blog entry about my book on Quantum Measurement.

Check out the link below to read it.

https://www.cambridgeblog.org/2024/02/quantum-measurement-book-blog/

2/2/24

I am honored to be named to the Kennedy Chair in Physics, here at Chapman University.

Thanks go to the donor Parker Kennedy, University president Daniele Struppa, provost Norma Bouchard, and dean Mike Ibba for helping to make this award happen.

More details about the gift, endowed chairs can be read here. Another gift to our new math, physics, and philosophy program is described here.

1/29/24

My new book, Quantum Measurement, Theory and Practice, is now available for pre-order.   Co-authored with Irfan Siddiqi, it is being published by Cambridge University Press.

You can pre-order it at Amazon now from this link.  Both hardcover and electronic formats are available to purchase.  The book is expected to be released on February 15.

12/22/22

Research updates:  Apologies for the less-than-frequent updates to this research news page over the past few months.  It is not that there is nothing going on - on the contrary, I have been so busy, I have not had a chance to give our new updates.  Here are a few highlights from the past few months:

We've had not 1, but 2 Editor's Suggested publications!

• Analog Quantum Simulation of the Dynamics of Open Quantum Systems with Quantum Dots and Microelectronic Circuits, Chang Woo Kim, John M. Nichol, Andrew N. Jordan, and Ignacio Franco, PRX Quantum 3, 040308 – Published 17 October 2022

In this paper, we propose a new kind of quantum bath simulator using quantum circuits to simulate environments experienced by chemical reactions.  The basic idea is to scale the timescales and energies applied to gate-defined quantum dots.

• Thermodynamics of quantum measurement and Maxwell's demon's arrow of time, Kagan Yanik, Bibek Bhandari, Sreenath K. Manikandan, and Andrew N. Jordan, Phys. Rev. A 106, 042221 – Published 27 October 2022

In this paper, we discuss a quantum mechanical version of Maxwell's demon, where measurements are made by the demon - that can be weak or continuous, and feedback applied to control the work and heat extracted from the system.  We discover close connections between thermodynamic quantities and our measure of the arrow of time.

We also had this nice paper published in PRL, focusing on thermal resources for quantum measurements:

• Energetic Cost of Measurements Using Quantum, Coherent, and Thermal Light, Xiayu Linpeng, Léa Bresque, Maria Maffei, Andrew N. Jordan, Alexia Auffèves, and Kater W. Murch, Phys. Rev. Lett. 128, 220506 – Published 3 June 2022.

In this paper, we showed how thermal light can be used as quantum measurement readout, and that it is surprisingly good at it.

Check out our publications page for many more cool papers.  This has been a very productive year - we published and posted 16 papers so far!

12/22/22

Congratulations to John Steinmetz on the successful defense of his PhD dissertation!  His thesis is titled "Weak Measurement: Applications to Quantum Computing and Parameter Estimation"

5/10/21

Continuous Error Correction published in Nature Communications 

Our article, "Experimental demonstration of continuous quantum error correction" in collaboration with the Siddiqi group, has been published.

We demonstrate the real-time detection and correction of quantum bit-flip errors using a continuous measurement process.   The two "parities" of three qubits are readout using the physics of continuous quantum measurement.  When a parity changes, a correction pulse is applied to restore the quantum state.  The challenging part is to know when the detected change is actually an error, or just noise.  We employ filtering techniques to get high-confidence results that an error is present.

11/2/21

Paper published in Nature Communications 

Our article "Enhanced on-chip phase measurement by inverse weak value amplification" together with Jaime Cardenas and colleagues is published in Nature Communications.

This work designed a new kind of integrated optical chip and implemented enhanced sensing of optical phase and frequency.  We use multi-mode interferometers to realize a "weak value amplification" effect.  Our current demonstration of weak value amplification in an integrated optical chip paves the way to incorporate weak value based techniques for quantum optical technologies in this scalable and robust platform.  

Update:  The University of Rochester has a nice article posted in their newsroom:

7/12/21

New job

I have accepted the position of Co-Director of the Institute for Quantum Studies at Chapman University.  My position there begins September 1.  I retain a research professorship at the University of Rochester, and continue to lead a research group located there.  Quantum nonlocality!

6/8/21

Congratulations!

Jing Yang, Sreenath Kizhakkumpurath, and Philippe Lewalle all received their PhDs in physics under my supervision.  

Phil's dissertation won the "Outstanding Dissertation Award" from the University of Rochester.

Additionally, Robert Czupryniak won the Okubo prize for the best performance in the first year graduate physics classes.  Well done, all!

4/26/21

Our recent PRL featured in Phys.org

It was a pleasure to read the article "A two-qubit engine powered by entanglement and local measurements", by Ingrid Fadelli, and published on Phys.org as a featured article.

Alexia gave a very nice interview outlining the significance of our results and how the field can further develop.  I'm glad our coining of the phrase "quantum energetics" was mentioned.

3/25/21

New publications

We have several new papers and preprints published on the Publications section of the website, which I encourage you to look at.  I want to highlight two newly published papers.

In a Templeton Foundation funded paper with Alexia Auffeves, Kater Murch, and students and postdoc Léa Bresque, Patrice A. Camati, Spencer Rogers, our work "Two-Qubit Engine Fueled by Entanglement and Local Measurements" has been published today in Physical Review Letters.  The editors have selected it as an "Editor's suggestion", which is a happy occasion.  You can see it featured on the main homepage of PRL.

Additionally, we published a paper, "Quantum measurement arrow of time and fluctuation relations for measuring spin of ultracold atoms", together with Maitreyi Jayaseelan, Sreenath K. Manikandan & Nicholas P. Bigelow in the publication: Nature Communications 12, 1847 (2021).  This work concerned some very nice experiments in the group of Nick Bigelow dealing with cold atoms, and how we could interpret the results in terms the arrow of time in a quantum measurement.  The work was supported by the NSF.

2/8/21

Multiple postdoc offers x 3.

Congratulations to my PhD students with an anticipated graduation date of this spring.  Happily they have all received multiple postdoc offers.

Jing Yang will join the group of Aldolfo del Campo in Luxembourg.

Sreenath Kizhakkumpurath will become a postdoc fellow associated with the Wallenberg Initiative on Networks and Quantum Computing, at Nordita in Stockholm, Sweden

Philippe Lewalle will join the group of Birgitta Whaley, at UC Berkeley.

Congratulations to all on finding excellent positions!

1/30/21

Welcome to Bibek Bhandari!  Bibek joined the group as a postdoc, after completing his PhD in physics from the Scuola Normale Superiore di Pisa , working with  Rosario Fazio and  Fabio Taddei.  He is an expert in quantum thermodynamics and thermal machines at the nanoscale.

10/16/20

Thanks to Lindsey Valich for writing a nice article about a new research grant from the John Templeton Foundation concerning "Thermodynamics of Quantum Information: Engines, Measurement, and Entropy".  Together with my co-PIs, Alexia Auffèves and Kater Murch, we are looking forward to working more on this topic.

Update:  This story is covered on 

SciTech Daily

Science Daily

10/16/20

We've posted a number of great papers to the arXiv in the past few days.  I find it hard to keep up with all the activity, so I haven't been able to give them the attention they deserve on this news portion of my website.  I hope to discuss them in colloquial terms as they are published.

• "Stochastic Thermodynamic Cycles of a Mesoscopic Thermoelectric Engine", R David Mayrhofer, Cyril Elouard, Janine Splettstoesser, Andrew N Jordan, arXiv:2010.06853

This paper examines a thermoelectric heat engine based on Coulomb-coupled quantum dots from the point of view of stochastic cycles.  We demonstrate the engine can operate as cycles that produce work - but crucially, are non-periodic.  There have been claims in the literature this is not possible, but we show how it works.  I learned a lot about graph theory and entropy production during this project.

• "Autonomous quantum absorption refrigerators", Sreenath K. Manikandan, Étienne Jussiau, Andrew N. Jordan, arXiv:2010.06024

This paper takes an earlier heat engine design of mine and collaborators using resonant tunneling quantum dots, and reimagines it as an absorption refrigerator.  In this case, there is no external power driving the fridge, rather a very hot thermodynamic reservoir.  You "cool by heating"!

• "Quantum erasing the memory of Wigner's friend", Cyril Elouard, Philippe Lewalle, Sreenath K. Manikandan, Spencer Rogers, Adam Frank, Andrew N. Jordan, arXiv:2009.09905

This article gives our take on a controversial paper by Frauchiger and Renner, who claim quantum theory is internally inconsistent.  This claim is based on a "Wigner's friend" type argument involving nested observers.  Our paper reformulated their argument in the context of a simple single-photon interferometer.  We then demonstrate that the contradictory properties giving rise to their paradox do not appear in the same experimental context - rather you have to do different experiments to see them.  One of those experiments involves erasing the memory of Wigner's friend! One may wonder if you could design a more clever experiment than ours to exhibit these contradictory properties at once.  We show that is impossible by showing the operators corresponding to the properties of interest do not all commute with one another.  Therefore within quantum mechanics, they cannot take on well defined properties in a single experiment.  Paradox solved.  I think this is a very important paper.

8/6/2020

Check out this fun video jointly produced by the American Chemical Society (ACS) and the Public Broadcasting System (PBS).  The narrator, Alex Dainis does a nice job narrating, and Samantha Jones is the writer and host of the series Reactions.  I helped them get the physics of refrigeration right.