What Does a QUANTUM PHYSICIST Do All Day? | REAL Physics Research at Cambridge University

Alexander Sneyd

1 Jun 202221:26

EducationalLearning

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TLDRJoin Dr. Hannah Stern as she takes us through the fascinating world of quantum mechanics, exploring the secure communications potential of quantum entanglement. Learn about her journey from New Zealand to Cambridge and her hands-on work with 2D materials like hexagonal boron nitride, which emit single photons crucial for unhackable quantum communication technologies. Hannah's story highlights the adventure of scientific discovery and the importance of mentorship and curiosity in the field of quantum physics.

Takeaways

🌟 Quantum mechanics is a fascinating field of science responsible for phenomena like quantum tunneling and entanglement.
👩‍🔬 Dr. Hannah Stern is a hands-on experimental scientist focusing on quantum mechanics, particularly light and its applications in secure communication technologies.
🔬 The research in Dr. Stern's lab revolves around materials that can form the basis of quantum communication and encryption technologies to create unhackable systems based on quantum mechanics.
💡 The security of quantum communication lies in the use of single photons, which change state upon measurement, alerting the sender and receiver to any interference.
🚪 The lab operates in a clean room environment to prevent dust from interfering with the fabrication of small structures for their quantum devices.
📏 The material of interest in the lab, hexagonal boron nitride, is a two-dimensional material that emits single photons when it has defects in its lattice.
🔄 The process of creating the material involves growing it in a reactor, cleaving it off the surface, and cleaning it with chemicals or iron bombardment.
🔎 Researchers use a confocal microscope to investigate the light emitted by the material and identify atomic-scale regions that emit a high count rate of photons.
🌐 The ultimate goal is to develop quantum communication technologies that can be deployed widely for secure messaging, but such technologies are still a decade away from commercial availability.
🧗‍♀️ Dr. Stern's journey into quantum physics involved a non-linear path, starting with an undergraduate degree in chemistry and eventually leading to her PhD at Cambridge.
🏞️ Dr. Stern emphasizes the importance of having mentors and being curious and brave in pursuing a career in science and quantum physics.

Q & A

What is quantum mechanics known for?
-Quantum mechanics is known for its cool and incredible effects such as quantum tunneling and quantum entanglement.
What does Dr. Hannah Stern do as a hands-on experimental scientist?
-Dr. Hannah Stern works in a laboratory with optics, mirrors, and lasers, focusing on studying quantum mechanics, particularly light, and its applications in quantum communication and encryption technologies.
Why is the research on quantum communication important?
-The research is important because it aims to build technologies that are fundamentally unhackable, based on the laws of quantum mechanics, ensuring secure communication in the face of potential future threats from powerful computers.
How do single particles of light contribute to quantum communication security?
-Single particles of light, or photons, are used to send messages. If a photon is interfered with, its state changes, and this change is detectable, alerting the sender and receiver to a potential security breach.
What is the significance of the clean room in the laboratory?
-The clean room is crucial for fabricating very small structures as it prevents dust particles from contaminating the devices being made, which could ruin them.
What material is Dr. Stern's lab currently working with to produce single photons?
-The lab is working with a two-dimensional material called hexagonal boron nitride, which emits single photons when it has defects in its lattice.
How does the process of making hexagonal boron nitride involve a reactor and a clean room?
-The HBN is grown in a reactor on a particular surface. It is then transferred to a clean room where it is cleaved off, placed on another surface, and cleaned using chemicals or iron bombardment to prepare it for experiments.
What is the role of the confocal microscope in the lab's research?
-The confocal microscope is used to investigate the light emitted by the material. It allows the researchers to stimulate the material to eject single photons, which are then directed towards a detector to measure their emission over time.
How does the lab identify atomic scale regions that emit a lot of photons?
-The lab uses a green laser to scan the sample, creating a map of the light emitted by each point in the material. They look for bright spots on this map, which indicate atomic scale regions with high photon emission rates.
What is the significance of the superposition state of photons in quantum communication?
-The superposition state allows photons to exist in multiple states simultaneously. If an eavesdropper interferes with the photon, its state collapses, alerting the sender and receiver to the interference, thus ensuring the security of the communication.
What advice does Dr. Stern have for those interested in pursuing a career in quantum physics or related fields?
-Dr. Stern advises finding a mentor, being curious, confident, and brave enough to step out of one's comfort zone, as it can lead to rewarding experiences and opportunities.
How does Dr. Stern describe her PhD experience at Cambridge?
-Dr. Stern describes her PhD experience as an adventure, highlighting the support from her group, the opportunity to study a subject she was passionate about, and the chance to engage in other activities like rock climbing and making friends outside of academia.

Outlines

00:00

🌟 Introduction to Quantum Mechanics and Meeting Dr. Hannah Stern

The video begins with an introduction to quantum mechanics, highlighting its fascinating effects like quantum tunneling and entanglement. The host is joined by Dr. Hannah Stern, a quantum physicist, to discuss her work and the field. Dr. Stern explains that she is an experimental scientist working with optics and lasers to study quantum mechanics, specifically focusing on light. The broader research question her lab addresses is the development of materials for quantum communication and encryption technologies, aiming to create unhackable communication systems based on quantum mechanics principles.

05:05

🚀 Fabricating Quantum Materials in a Clean Room

The segment delves into the process of fabricating quantum materials in a clean room to prevent contamination by dust particles, which could ruin the tiny structures being created. Dr. Stern's lab works with a two-dimensional material called hexagonal boron nitride, which emits single photons when it has defects. The process of growing this material, cleaving it off the original surface, and cleaning it is described. Additionally, the lab evaporates metals like gold onto the material to create new structures for advanced experiments.

10:09

🔬 Experimenting with Single Photons and Quantum Emission

The video continues with an explanation of how the lab stimulates the material to emit single photons, which are then directed towards a detector for measurement. The use of a confocal microscope to investigate the light emitted by the material is highlighted. The lab uses an open microscope setup with mirrors and lenses to control the light paths. The experiment involves scanning a sample with a green laser to create a map of light emission, identifying atomic-scale regions that emit a high number of photons with a narrow energy range, which are useful for quantum communication technologies.

15:12

🌐 Dr. Stern's Journey into Quantum Physics and Her Experiences

Dr. Stern shares her personal journey into quantum physics, starting with her undergraduate studies in chemistry in New Zealand. She discusses her break to hike the Milford Track, where she met a physicist who encouraged her to consider Cambridge. Her experiences working at Victoria University in Wellington and eventually pursuing her PhD at Cambridge are detailed. She also talks about her work on materials for solar energy harvesting and organic semiconductors, which led her to quantum optics.

20:14

🔐 The Security of Quantum Communication and Future Prospects

The discussion turns to the security aspects of quantum communication, explaining how single photons in a superposition state can be used to send messages securely. If an eavesdropper interferes with the photon, the state changes, alerting the sender and receiver to a breach. The video notes that while commercial quantum technologies are still years away, the lab's research aims to expand the understanding of materials and defects for better technologies. Dr. Stern emphasizes the importance of having a mentor and being curious and brave in pursuing a career in science.

🎥 Behind the Scenes and Final Thoughts

The video concludes with a behind-the-scenes look at the filming in Professor Mete's lab and acknowledgments to all those who participated. The host expresses gratitude to Dr. Stern for her inspiring insights and for allowing the filming to take place. The video ends with a call to action for viewers to subscribe to the channel and share their interests in science topics they'd like to see covered in future videos.

Mindmap

Keywords

💡Quantum Mechanics

Quantum mechanics is a fundamental theory in physics that describes the behavior of matter and energy at the atomic and subatomic scales. It is known for its strange and counterintuitive principles, such as superposition and entanglement, which are essential for understanding phenomena like quantum tunneling. In the video, quantum mechanics is the core subject of the scientist's research, particularly as it relates to quantum communication and encryption technologies.

💡Quantum Entanglement

Quantum entanglement is a physical phenomenon that occurs when pairs or groups of particles interact in such a way that the quantum state of each particle cannot be described independently of the state of the others, even when the particles are separated by large distances. This principle is crucial for quantum communication, as it allows for the creation of secure communication channels that rely on the instantaneous correlation of entangled particles. In the video, the concept is used to explain the security features of quantum communication technologies.

💡Quantum Communication

Quantum communication refers to the use of quantum mechanical properties, such as superposition and entanglement, to transmit information securely. It leverages the principles of quantum mechanics to create communication channels that are theoretically unhackable due to the nature of quantum states. The video discusses the development of such technologies, which are designed to be more secure than traditional communication methods.

💡Photons

Photons are elementary particles that represent the quantum of any electromagnetic radiation, including light. They are massless and travel at the speed of light. In quantum communication, single photons are used to carry information because they can exist in superposition states and their interaction with matter can be precisely controlled. The video explains how the manipulation of photons is central to the field of quantum optics and the development of quantum technologies.

💡Hexagonal Boron Nitride

Hexagonal boron nitride (h-BN) is a two-dimensional material composed of boron and nitrogen atoms arranged in a hexagonal lattice. It is similar in structure to graphene but has different electronic properties, making it an excellent insulator. In the context of the video, h-BN is of interest because it can emit single photons when it has defects in its lattice, which is useful for quantum optical applications.

💡Clean Room

A clean room is a controlled environment with very low levels of pollutants such as dust, airborne microorganisms, aerosol particles, and chemical vapors. It is used in various industries that require a contamination-free environment, including the fabrication of semiconductors, optics, and nanomaterials. In the video, the clean room is essential for the fabrication of the quantum materials, as even a single dust particle can ruin the delicate structures being created.

💡Superposition

Superposition is a fundamental principle of quantum mechanics where a physical system exists in multiple states or configurations simultaneously. A photon, for example, can be in a superposition of different polarization states. Measuring the system causes it to collapse into one of the possible states. This property is harnessed in quantum communication to create secure messages that can detect eavesdropping.

💡Quantum Encryption

Quantum encryption is a method of securing communication by using the principles of quantum mechanics to encode and protect data. It is considered to be more secure than traditional encryption methods because it relies on the fundamental properties of quantum particles, making it immune to many types of hacking attempts. The most well-known protocol is Quantum Key Distribution (QKD), which uses the quantum properties of photons to generate a secure key for encrypting and decrypting messages.

💡Confocal Microscope

A confocal microscope is an imaging system that uses a laser to scan samples and a pinhole to reject out-of-focus light, resulting in high-resolution, three-dimensional images. It is particularly useful for imaging thin, transparent samples and is a valuable tool in the study of materials at the microscale. In the video, a confocal microscope is used to investigate the light emitted by quantum materials, allowing researchers to map the emission of single photons.

💡2D Materials

Two-dimensional (2D) materials are a class of materials composed of a single layer of atoms. They exhibit unique electronic, optical, and mechanical properties that are distinct from their bulk counterparts. Graphene is a well-known example of a 2D material. In the context of the video, 2D materials like hexagonal boron nitride are being researched for their potential applications in quantum technologies, including quantum communication and sensing.

Highlights

Quantum mechanics is a fascinating field responsible for phenomena like quantum tunneling and entanglement.

Quantum entanglement can occur between the quantum states of particles in the human brain.

Dr. Hannah Stern is a hands-on experimental scientist working with optics, mirrors, and lasers to study quantum mechanics.

Dr. Stern's lab focuses on materials for quantum communication and encryption technologies to create unhackable communication systems.

Quantum communication technologies use single particles of light, or photons, to transmit messages securely.

The security of quantum communication is based on the principle that any interference with a photon changes its state, alerting the sender and receiver.

Dr. Stern's lab works with two-dimensional materials, such as hexagonal boron nitride, which emit single photons at defects in the lattice.

The process of creating these materials involves growing them in a clean room to prevent dust from interfering with the tiny structures.

To study the emitted single photons, Dr. Stern's team uses a confocal microscope and other optical components.

The team maps the light emitted by the material to identify atomic-scale regions that emit a high number of photons.

Dr. Stern's journey into quantum physics began with an undergraduate degree in chemistry and a hiking trip that led to a conversation with a physicist.

Dr. Stern's PhD involved studying materials for solar energy harvesting and organic semiconductors before focusing on quantum optics.

Commercial quantum technologies are still years away, but research in labs like Dr. Stern's is expanding the toolkit for future technologies.

Dr. Stern advises aspiring scientists to find a mentor, be curious, and take brave steps out of their comfort zone.

Quantum technologies in development include secure communication, quantum sensing, and quantum computation.

Dr. Stern's experience in Cambridge was an adventure, highlighting the importance of work-life balance in academia.

The video provides a behind-the-scenes look at the lab and the process of studying quantum mechanics, offering insights into the scientific process.

Transcripts

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QuantumPhysics CommunicationTech Unhackable ExperimentalScience PhotonEmission 2DMaterials CleanRoom Cambridge ScientificJourney Mentorship CareerAdvice