Events

Quantum Nano Centre (QNC) Room 0101, 200 University Avenue West, Waterloo, ON

IQC Colloquium, Harry Buhrman - QuSoft

One of the major challenges in computer science is to establish lower bounds on the resources, usually time, that are needed to solve computational problems. This holds in particular for computational problems that appear in practise. One way towards dealing with this situation is the study of fine- grained complexity where we use special reductions to prove time lower bounds for many diverse problems based on the conjectured hardness of some key problems.

Impromptu Whiteboard Poster Session

Quantum Nano Centre (QNC) Room 1201, 200 University Avenue West, Waterloo, ON

This week’s student seminar will take place in the form of an impromptu whiteboard poster session, where attendees will be divided into groups and will discuss each other's current work using the whiteboard. This is to encourage students to talk about their work in progress, and practice communication skills by talking to non-experts (quantum is a big field!). As always, pizza will be provided for attendees after the seminar.

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IQC Colloquium - Alex May, Perimeter Institute

Quantum Nano Centre (QNC) Room 0101 200 University Ave West, Waterloo Ontario

The subject of quantum gravity seeks to understand gravitational physics within the framework of quantum mechanics. Increasingly, tools from quantum information, complexity, and cryptography have been brought into this challenging area. Here, I describe a set of connections between quantum gravity, specifically the AdS/CFT correspondence, and a set of cryptographic primitives studied in information theoretic cryptography and position-verification. The cryptographic perspective provides new insights into how gravitational physics can be recorded into quantum mechanics, and led to new gravitational conjectures in AdS space. These conjectures were then proven gravitationally. Conversely, the gravitational perspective has suggested new relationships among these cryptographic primitives, and these relationships were then proven within quantum cryptography. I comment on some directions this cryptography-gravity relationship may lead in the future.  

IQC Colloquium - Mio Murao, The University of Tokyo

Quantum Nano Centre (QNC) Room 0101 200 University Ave West, Waterloo Ontario

Please note start time 3:00 PM

Efficiently learning properties of unknown quantum objects is a fundamental task in quantum mechanics and quantum information. When there are two unknown quantum objects, and if we want to learn just the relationship between the objects, a method to directly compare the two objects without identifying their descriptions is preferable, especially when the number of available copies of each target object is limited. In this work, we investigate the comparison of unknown unitary channels with multiple uses of the unitary channels based on the quantum tester formalism.  We obtain the optimal minimum-error strategy and the optimal unambiguous strategy of unitary comparison of two unknown d-dimensional unitary channels when the number of uses of the channels satisfies a certain condition. These optimal strategies are implemented by parallel uses of the unitary channels, even though all sequential and adaptive strategies implementable by the quantum circuit model are considered. When the number of the smaller uses of the unitary channels is fixed, the optimal averaged success probability is achieved by a certain number of uses of the other channel. This feature contrasts with the case of pure-state comparison, where adding more copies of the unknown pure states always improves the optimal averaged success probability. It highlights the difference between corresponding tasks for states and channels, which has been previously shown for quantum discrimination tasks.  

Reference: Y. Hashimoto, A. Soeda and M. Murao, Comparison of unknown unitary channels with multiple uses, arXiv:2208.12519

IQC Seminar - Johannes Prell, Institute of Communication and Navigation, OSL German Aerospace Center (DLR) Oberpfaffenhofen, Germany

Quantum Nano Centre (QNC) Room 0101 200 University Ave West, Waterloo Ontario

Satellite based laser communication technology both classical and QKD (Q uantum K ey D istribution is gaining popularity and being increasingly commercial i zed . Optical ground stations serve as the receiv ing station in satellite to ground scenarios. The DLR institute of Communications and Navigation hosts an experimental optical ground station for research and demonstration purpose. Supporting increasingly demanding technical requirements from current and futu re missions and technology demonstrations, it was decided to replace the 40cm Cassegrain telescope an equip the new one with Nasmyth Ports for direct experiments, a Coudé Path to the lab and an Adaptive Optics System . This new 80cm (31.5inch) main apertur e diameter i nstrument is a Nasmyth Design Ritchey Chretien telescope The special feature is the C oudé P ath which is guiding the received light onto an optical table in a lab oratory room below the telescope mount (see figure 1 The usage of the Coudé Path is new implemented at DLR and offers a wide possibility for several different experiments with the same setup The optical propaga tion through a custom designed lens system inside the coudé path is optimized for wavelength s used for optical communication, like 589nm, 850nm, 1064nm and 1550nm. It is possible to use the setup as a receiving station and also as a transmitting facility f or beacon lasers . The transmitt ing system ca n be installed either beside the telescope as a side installation or even launched from the optical table through coudé path and telescope directly

The optical Experiment table in the lab is equipped with an Adaptive Optics ( System including fibe r coupling. This system uses a Shack Hartmann Wave front sensor, designed to match a deformable mirror in the “ f ried g eometry”. The system couples the light into a single mode fibe r , which can be con nected to a coherent or Quantum encrypted communications system. [ The telescope itself has four usable Nasmyth ports The first one is reserved for the coudé pa th, t wo others are equipped with optical benches directly on the telescope, and on the last one has a fixed classical laser communication receiving setup including two cameras one visible light and one infra red and a signal receiving united is installed References

[1] Andrew Paul Reeves, Ilija R. Hristovski, Alexandru Octavian Duliu, Stefanie H äu sler, Hela Friew Kelemu, Pia Lützen, Florian Moll, Eltimir Peev, Juraj Poliak, Amita Shrestha, Joana Sul Torres; Adaptive Optics Corrected Bi Directional Links with a Geo Stationary Satellite from the DLR KN Optical Ground Station Figure 1 OGSOP System Overvi ew

Live on YouTube

Join us for Quantum Today, where we sit down with researchers from the University of Waterloo’s Institute for Quantum Computing (IQC) to talk about their work, its impact and where their research may lead.

In this special session, we’ll be joined by Joan Arrow and Özge Gülsayin of the Quantum Ethics Project, a team of researchers exploring the intersection of quantum and society. We’ll discuss how to advocate for the responsible and inclusive development of quantum technologies through education and research, and why an ethics lens is important in even the early stages of technological innovation.

Online webinar through Microsoft Teams

The University of Waterloo and Mitacs will be holding a joint webinar on Thursday, November 23^rd at 10am to share information about their new Globalink Research Award (Quantum stream), which provides funding for bilateral student travel with international university labs.

In this session, Amanda Green and Etienne Pineault, Senior Advisors with Mitacs, will provide information and updates on how to leverage Mitacs funding to build collaborative research projects with international university partners. 

Following the presentation, we will answer your questions about finding a partner, deciding on Mitacs eligibility and navigating program requirements (including how to work with our team to submit successful funding applications). Regan Child, International Grants and Contracts Manager with the Office of Research, will be on hand to offer assistance.

Tight bounds for Pauli channel learning with and without entanglement

Quantum Nano Centre, 200 University Ave West, Room QNC 1201
Waterloo, ON CA N2L 3G1

Quantum entanglement is a crucial resource for learning properties from nature, but a precise characterization of its advantage can be challenging. In this work, we consider learning algorithms without entanglement as those that only utilize separable states, measurements, and operations between the main system of interest and an ancillary system. Interestingly, these algorithms are equivalent to those that apply quantum circuits on the main system interleaved with mid-circuit measurements and classical feedforward. Within this setting, we prove a tight lower bound for Pauli channel learning without entanglement that closes the gap between the best-known upper bound. In particular, we show that Θ(n^2/ε^2) rounds of measurements are required to estimate each eigenvalue of an n-qubit Pauli channel to ε error with high probability when learning without entanglement. In contrast, a learning algorithm with entanglement only needs Θ(1/ε^2) copies of the Pauli channel. Our results strengthen the foundation for an entanglement-enabled advantage for Pauli noise characterization. We will talk about ongoing experimental progress in this direction.

Reference: Mainly based on [arXiv: 2309.13461]

Optimization of the Optical Infrastructure and Trapping Potential for a Quantum Processor Based on Trapped Barium Ions

Quantum-Nano Centre, 200 University Ave West, Room QNC 2101
Waterloo, ON CA N2L 3G1

Supervisor: Kazi Rajibul Islam

Creating and probing laser-cooled atomic ensembles inside a hollow-core optical fibre

Quantum-Nano Centre, 200 University Ave West, Room QNC 2101
Waterloo, ON CA N2L 3G1

Supervisor: Michal Bajcsy