Measuring Quantum Entanglement

Note (1/29/23):  Funding for these positions is anticipated but not yet confirmed.

In this project, we will study verification of quantum entanglement in partially entangled pairs, a capability essential for the smooth operation of a future “quantum internet.”  Entangled pairs are necessary for numerous secure communication protocols, in which the equipment needed to carry out the protocols is much simpler than the equipment needed to produce the entangled particles.  Individual users will be able to perform quantum communication and cryptography using entangled pairs provided by a third party.  In this setting, it is important to identify reliable and efficient measurements the users can perform to test that they are truly receiving entangled pairs.  Such measurements are called entanglement witnesses.  The best-known entanglement witnesses require a large number of different measurements by users, and are only sensitive to entanglement that is near-perfect in quality.  Our group has studied witnesses proposed in the literature to overcome one or both of these issues, and has proposed new adaptive-measurement strategies to maximize the chance of witnessing entanglement with a limited number of measurements.  In summer 2023 we plan to continue improvement of our adaptive strategies and perform experiments demonstrating how they work on our entangled-photon apparatus.

For students with appropriate interest and background, there is also a possibility of working on a more purely theoretical project on distinguishability of hyperentangled states using linear evolution and local measurement.

Please write a short essay response to this question:  What interests you most about working on this project and in this research group?  How does this project align with your existing skills and experience, and/or with your future goals?

Name of research group, project, or lab
The Lynn Lab (HMC Quantum Optics Group)
Why join this research group or lab?

Research in the Lynn Lab explores aspects of quantum entanglement.  Entangled pairs of particles exhibit correlated properties that cannot be understood via classical reasoning.  Though the concept of entanglement is nearly 100 years old, currently entanglement is in the spotlight as an essential resource for quantum computing and communication.  Some fundamental aspects remain poorly understood, particularly for partially entangled pairs of particles and entangled particles whose internal structure is more complicated than the canonical 'quantum bit.'  Our work this summer tackles aspects of entanglement with experimental and theoretical tools.

Along with research on the experimental project itself, Lynn Lab members are encouraged to participate in a journal club with other summer researchers in the physics department, and to take part in social and extracurricular opportunities in the department and college's summer research community.

Logistics Information:
Project categories
Student ranks applicable
Student qualifications

There is room in this research for approaches that are primarily experimental, involving day-to-day experimental optics techniques that can be learned in the lab, or primarily theoretical.  Experimental experience with optics is an asset for some approaches to the project and should be mentioned.  Comfort with reading and editing Python and/or Matlab code is a plus; for some aspects of the project, familiarity with neural networks (e.g. using Keras) is helpful.  Theoretical background can be taught during the summer, but some familiarity with quantum mechanics (Ph52/84/116) and Dirac notation (Ph84/116) is a plus.  Independent work, strong communication skills, and willingness to ask questions are valuable attributes for a group member.

Time commitment
Summer - Full Time
Paid Research
Number of openings
Techniques learned

Students will learn fundamentals of quantum entanglement and its application to quantum cryptography.  Experimental directions will build students' optics skills, especially in the area of polarization control and measurement.  New students will be exposed to quantum mechanics and quantum information, while experienced quantum students will apply their theoretical knowledge to current applications.

Contact Information:
Theresa Lynn
Principal Investigator
Name of project director or principal investigator
Theresa Lynn
Email address of project director or principal investigator
2 sp. | 20 appl.
Hours per week
Summer - Full Time
Project categories
Optics (+1)