Psiket Webinars

Topological superconductivity is one of the emerging fields in physics, important both from a fundamental perspective and for its applications, especially in fault-tolerant quantum computing. One of the intriguing routes toward realizing such phases is the use of suitable impurities in superconductors. These impurities can give rise to a useful state in the superconducting mechanism known as the Yu–Shiba–Rusinov (YSR) state. When a large number of such impurities are arranged in a chain or cluster, they can provide a platform for the emergence of topological superconductivity and Majorana fermions. In this talk, I will first give a brief overview of superconductivity and its properties. I will then explain why impurities can play a decisive role. Next, I will show how these impurities can become a platform for discovering new quantum phases. Finally, I will point to the prospects of this exciting field in the design of quantum systems.

We are familiar with conventional phases of matter such as gas, liquid, and solid, which are equilibrium phases arising from thermodynamic balance. In these cases, the presence of a thermal bath is essential for classical systems to reach thermodynamic equilibrium. A natural question then arises: for a quantum system, is thermodynamic equilibrium defined in the same way as in classical systems, and is a thermal bath required? Moreover, are there systems that, without reaching thermodynamic equilibrium, still exhibit distinctive features of their own? In other words, can we meaningfully speak of dynamical quantum phases that are neither classical equilibrium states nor defined by a thermal bath? In this talk, I will present examples of such quantum systems that demonstrate the emergence of dynamical quantum phases. I will also briefly discuss transitions between different dynamical quantum phases and highlight some practical examples.

Experiments in the field of atomic physics, in addition to providing insights into the fundamental structure of atoms and their interactions with electromagnetic fields, have numerous applications that are gradually finding their way into industry and everyday life. Examples include atomic sensors, atomic clocks, devices based on cold-atom interferometry, and technologies utilizing Rydberg atoms, among others. One of the most important prerequisites for conducting all these experiments is the precise identification and resolution of atomic energy levels, as well as the possible transitions between them. In this presentation, after reviewing atomic transitions and their characterization through laser spectroscopy, we will discuss the role of atomic transitions in various applications and how they can be exploited.

فرایند خنک سازی و کاربرد اتمهای سرد اکنون به دهه چهارم بلوغ خود ورود پیدا کرده است. یکی از مهمترین کاربردهای اتمهای سرد، حوزه گرانش و یا شتاب سنجی است، که دقتهای بی سابقه ای از سنجش این پارامترها ارایه کرده اند. اندازه گیری شتاب مکانیکی و یا گرانشی دارای اهمیت در چند حوزه از جمله در فیزیک بنیادی است، جایی که ممکن است اندازه گیریهای دقیق، اصل هم ارزی نسبیت و قوانین نیوتن را هدف ارزیابی مجدد قرار دهد، و یا در کشف امواج گرانشی مورد استفاده قرار گیرد. اما در حوزه فناوری، اکنون محصولات تجاری بر اساس اتمهای سرد روانه بازار شده اند. دقت اندازه گیری شتاب گرانشی در این دستگاهها به رقم بی سابقه 10^(-8) m/s^2 رسیده است، که دو مرتبه بزرگی از حساس ترین شتاب سنجهای کلاسیکی با ساختار MEMS (پیزوالکتریک)، دقیقتر هستند. از اینرو، کاربرد این اسبابها در سامانه های ناوبری که دقت بالا هم در شتاب خطی و هم زاویه ای مورد تقاضا است، مطرح می باشد. ولی، شتاب سنجهای اتمی هنوز کند عمل میکنند و کاربرد آنها فعلا محدود به مسایلی است که تغییرات اندک شتاب جاذبه، بدلیل وجود معادن، و یا مخازن گاز یا نفت و حتی کشف تهی جاهای پنهان در زمین، اتفاق می افتد. پروژه های مشترکی هم در حال پیگیری است که هدف ارسال این سامانه ها به فضا و مطالعه فیزیک بنیادی است. بدلیل عدم وجود جاذبه، دقتها خیلی افزایش پیدا میکنند و چشم انداز، دستیابی به آشکارساز اینرسی کوانتومی با دقت 10^(-12) m/s^2 (در پهنای باند 1 هرتز) می باشد.

Spontaneous parametric down-conversion process (SPDC) is a nonlinear optical process in which a pump photon is automatically converted into an entangled photon pair with a lower frequency of signal and idler. SPDC is the heart of many quantum optics experiments, such as quantum cryptography, quantum computer, quantum biology, quantum metrology, as well as experiments on the fundamental laws of quantum physics. In this lecture, we will talk about photon pair generation arrangements in entanglement and its application in quantum interferometers, imaging and quantum measurements, etc.

The development of quantum technology has so far raised many hopes for different target markets. Sometimes the approach and driving engine of this technology is evaluated for its special functions and sometimes for its money-making future. This presentation evaluates the role and impact of quantum technology in the country's technology development by proposing a hybrid ecosystem.

In this lecture, we will discuss the fascinating field of optomechanics, where photons and phonons interact with each other and create an interesting interdisciplinary field. In this regard, the expression of unique integrated photonic-phononic micron systems will be discussed to study the interaction between photons and phonons. About the mechanism of phonon production in this context and the concept of phonons as the basic unit of mechanical vibrations in photonic structure, it will be mentioned, and in the following, different laboratory methods of studying phonons in nanoscale systems will be investigated.