😱 نخستین هواپیمای فضایی با قابلیت حمل مسافر و بار 😱

لینک گزارش
@PDATLAB

School of Physics: HEPCo Weekly Seminar Series


Speaker

Sajad Aghapour


Affiliation

Max Planck Institute for Gravitational Physics (Albert Einstein Institute)


Title of talk

Interaction of Kerr-Newman Electromagnetic Fields



برهم‌کنش میدان‌های کر-نیومان الکترومغناطیس

Date and time

Tuesday, September 10th, 2024 (Shahrivar 20th, 1403), 2:00 pm (Tehran zone)

Link

https://www.skyroom.online/ch/schoolofphysics/highenergyseminar

Abstract

In this talk, I will discuss some properties of the Kerr-Newman (KN) Electromagnetic Fields, which is the G → 0 limit of the KN solution of Einstein-Maxwell equations. In this limit, the electromagnetic sector of the solution survives, while the background becomes locally flat with nontrivial topology. The discussion includes the complex transformation between the non-spinning Coulomb solution and the spinning KN, the g = 2 gyromagnetic ratio of the solution noted by Carter, and the corresponding multipole structure. The topological conserved charges of the electromagnetic field, i.e. the classical helicity and classical spin, are calculated for this solution. Moreover, we studied the interaction of two such solutions by evaluating the Lagrangian for the superposition of those fields. This yields a correction to the interaction potential beyond the Coulomb interaction due to the spin of the fields. The talk is based on: https://arxiv.org/pdf/2405.12602.

سلام

🔵 قابل توجه دانشجو‌های دکتری و محققان پسادکتری در گرایش ریسمان و هولوگرافی (دقت کنید این یک برنامه برای همکاری در کار تحقیقاتی نیست) :


Dear colleague,

Are you a PhD student or postdoctoral fellow who feels would benefit from guidance on your academic career, work-life balance, or other challenges from an experienced researcher within our string theory community? Or, are you a postdoc or faculty member who feels you can support a younger scientist in navigating their academic journey?

Consider applying to "Quantum Guides," a mentoring program designed specifically for the string theory community.

https://sites.google.com/view/mentoring-program-string-th/home
Applications are open until September 15. The program is open to everyone, but it is targeted to underrepresented groups.
We hope to count with you in this new academic year. Please forward this email to whoever might be interested (in particular, we seek mentors to accommodate the increasing global demand of mentees).We also apologize if you receive this email more than once.
Best regards,
Mariana Grana and Irene Valenzuela (program coordinators)



@sth_fum

🇺🇸 Post-Bac Opportunity - Junior/Assistant Specialist – The Space Sciences Laboratory 🇺🇸

As a Junior/Assistant Specialist on the UVEX project, you will be responsible for:
• Analyzing data and outputs from theoretical models.
• Writing and maintaining code for data processing and analysis.
• Attending project meetings and collaborating with team members.
• Writing documentation to support research and mission objectives.
• Presenting findings to the research team and at scientific conferences.

The position will report to Berkeley Astronomy Professor Dan Weisz.

This is an exciting opportunity to contribute to a major space mission and work alongside leading experts in the field. If you are passionate about space sciences and have a strong background in data analysis and coding, we encourage you to apply.
The UC academic salary scales set the minimum pay determined by rank and step at appointment. See the following table(s) for the current salary scale(s) for this position: https://www.ucop.edu/academic-personnel-programs/_files/2024-25/july-2024-scales/t24-b.pdf. A reasonable estimate for this position is $64,100 - $82,500

✅ غربالگری که تک فوتون‌ها را از حالت های چند فوتونی جدا می ‌کند

#اخبار_علمی_و_پژوهشی

دستگاهی که حالت‌های فوتونی را مرتب می‌کند، می‌تواند به یک جزء اصلی از کامپیوترهای کوانتومی تمام-نوری منجر شود. کنترل برهمکنش‌های بین فوتون‌ها می‌تواند به فناوری‌های جدیدی از جمله رایانه‌های کوانتومی تمام-نوری بیانجامد. ریچارد واربرتون Richard Warburton و همکارانش از دانشگاه بازل سوئیس با برداشتن ...

📣 متن کامل را در Instant View ⚡️ (دکمه پایین صفحه) و یا در وب‌گاه انجمن فیزیک ایران بخوانید:
🚩http://www.psi.ir/news2_fa.asp?id=4113

⏪ وب‌گاه انجمن فیزیک ایران:
🌍 http://www.psi.ir

✅ به کانال خبرى انجمن فیزیک ايران بپيوندید:
👇👇🏽👇👇🏽👇👇🏽👇
http://t.me/psinews

📗مقاله آموزشی «تعیّن ناقص مُدل‌ها در کیهان‌شناسی و مسئله توجیه اصل کیهان‌شناختی»

♦️فهرست مطالب:
1- تعیّن ناقص مدل‌ها در کیهان شناسی نوین
2- نقش اصل کیهان شناختی در رفع تعیّن ناقص مدل‌ها
3- بررسی شواهد و استدلال‌های موجود به نفع اصل کیهان شناختی
3- 1-‌ توجیه اصل کیهان‌شناختی برای جهان قابل مشاهده
3- 1-‌ 1- بررسی مستقیم داده‌ها
3- 1-‌ 2- آزمون اصل کیهان شناختی از راه پیامدهای آن
3- 1-‌ 3- استنتاج همگنی از همسان‌گردی
3- 2-‌ توجیه اصل کیهان‌شناختی برای کل کیهان
3- 2-‌ 1- پدید آمدن یک جهان همگن و همسان‌گرد از یک شرایط اوّلیه دلخواه و عام
3- 2-‌ 2- توان تبیینی اصل کیهان‌شناختی به عنوان شاهدی بر برقراری آن
3- 2-‌ 3- اصل کیهان‌شناختی به عنوان تعمیمی از اصل هموردایی عام
3- 2-‌ 4- استنتاج اصل کیهان‌شناختی از طریق استقراء

✍🏻حامد منوچهری کوشا
🔺تعداد صفحات: 10

🔴کانال علم، فلسفه و الهیات
🆔@TheoCosmology

🇨🇭برنامه دانشجویی دکترای سرن 2025 (فول فاند)🇨🇭

لینک گزارش
@PDATLAB

🇳🇱 PhD Program in Astronomy and Astrophysics at Leiden University 🇳🇱

Leiden Observatory invites applications for approximately 6-10 new PhD positions.

The four-year PhD program consists mostly of research under the supervision of one or more faculty members. Positions are available in all the research areas in which the Observatory is active. These include cosmology, galaxy formation and evolution, interstellar matter and star formation, stars and planetary systems, computational astrophysics, high energy astrophysics, laboratory astrophysics, astrochemistry, and instrumentation. More information about research at Leiden Observatory can be found at https://www.universiteitleiden.nl/en/science/astronomy/research

Leiden Observatory, founded in 1633, is the oldest university astronomy department in the world. With about 35 faculty, over 40 postdoctoral associates and about 65 PhD students it is the largest astronomy department in the Netherlands. Leiden is a charming university town with an international flair. Most Leiden researchers have an international background. English is the common language.

During their thesis, Leiden PhD students are paid as civil servants, which means that they earn competitive salaries (the current annual gross salary, including allowances, increases from about EUR 34,000 in year 1 to about EUR 43,000 in year 4) and are eligible for both social security and retirement benefits. PhD positions are funded for four years.

Application forms and instructions are available at https://local.strw.leidenuniv.nl/jobs/phd/. Applicants are requested to upload a curriculum vitae, a list of all university courses taken and trannoscripts of grades obtained, brief statements of research interests and experience, and the contact information for at least two referees.

School of Physics: HEPCo Weekly Seminar Series


Speaker

Nicolas Bern


Affiliation

New York University Abu Dhabi


Title of talk

From WIMPs to FIMPs with Low Reheating Temperatures


از ویمپز به فیمپز با بازگرمایش در دماهای پایین

Date and time

Tuesday, September 17th, 2024 (Shahrivar 27th, 1403), 2:00 pm (Tehran zone)


Link

https://www.skyroom.online/ch/schoolofphysics/highenergyseminar


Abstract

Weakly- and Feebly-Interacting Massive Particles (WIMPs and FIMPs) are among the best-motivated dark matter (DM) candidates. In this paper, we investigate the production of DM through the WIMP and FIMP mechanisms during inflationary reheating. We show that the details of the reheating, such as the inflaton potential and the reheating temperature, have a strong impact on the genesis of DM. The strong entropy injection caused by the inflaton decay has to be compensated by a reduction of the portal coupling in the case of WIMPs, or by an increase in the case of FIMPs. We pinpoint the smooth transition between the WIMP and the FIMP regimes in the case of low reheating temperature. As an example, we perform a full numerical analysis of the singlet-scalar DM model; however, our results are generic and adaptable to other particle DM candidates. Interestingly, in the singlet-scalar DM model with low-reheating temperature, regions favored by the FIMP mechanism are already being tested by direct detection experiments such as LZ and XENONnT.

School of Particles and Accelerators

Journal Club: Experiments & Phenomenology / Hybrid Format

Date:

Monday, Sep 16, 2024 / دوشنبه، 26 شهریور 1403

Time:

11:00 AM - 12:00 PM (Tehran time)

Speaker:

Dr. Seyedeh Sedigheh Hashemi



Affiliation:

School of Particles and Accelerators, IPM

Title:

Low-energy high-brightness electron beam dynamics based on slice beam matrix method



Title in Persian:

دینامیک بیم الکترونی کم انرژی و روشنایی زیاد با استفاده مدل ماتریسی



Abstract:

Preserving the phase space quality has been of crucial importance to high-brightness electron beam transport. Any driving source of beam performance limitations in such a transport system must be carefully examined in order to preserve the beam phase space quality. It is found that in the low beam energy, high bunch charge regime, space charge effect on the charged particle beam evolution can be complicated. It may be insufficient to analyze the beam properties through the envelope or lower order moments for the mere bulk of the beam. In this work we will study the space-charge-dominated, low-energy, high-brightness electron beam dynamics based on the slice beam matrix method. The slice beam matrix method, extended from the existing bulk beam analysis, is applicable to an arbitrary longitudinal bunch distribution and can thus take the nonlinear RF curvature into account. The semi-analytical sliced beam space charge model is constructed and assumes an axisymmetric beam in the presence of perfect conducting cylindrical pipe with circular cross section. We present in this paper the theoretical formulation, starting from single-particle dynamics, space charge field calculation, followed by the moment denoscription of a collection of particles, based on beam sigma matrix and longitudinal slice decomposition. We prove the equivalence between the beam matrix method and the envelope formalism in the presence of space charge effect, in both the transverse and longitudinal dimensions.



Based on: https://doi.org/10.1016/j.nima.2019.05.035

Meeting Place: Seminar Room, School of Particles and Accelerators, IPM

Link to Join Virtually: https://meet.google.com/bda-vsem-tuv

گروهی از دانشگاه استنفورد بستری را فراهم کرده‌اند که می‌توان برای قسمت‌های مختلف مقالات در سایت آرکایو arXiv، سوالات یا نظرات را مطرح کرد و در یک گفت و گو در این باره شرکت کرد.
متن اعلامیه شروع این بستر به شرح زیر است:

arXiv -> alphaXiv
Students at Stanford have built alphaXiv, an open discussion forum for arXiv papers.
You can post questions and comments directly on top of any arXiv paper by changing arXiv to alphaXiv in any URL!

@sth_fum

ویدیویی از فضای این بستر جدید.

@sth_fum

صرفا با تغییر
arXiv
به
alphaXiv
در صفحه مقاله مورد نظر به این محیط وارد می‌شوید. برای استفاده از این سایت باید ثبت نام کنید.

در صورتی که با پیامی مبنی بر نبودن دامنه ایمیل شما در لیست ایمیل‌های این سایت مواجه شدید صرفا عملیات ثبت نام را ادامه دهید و توجه به این هشدار نکنید.

برای نمونه من مقاله آخر ویتن را در این سایت باز کردم:
https://alphaxiv.org/pdf/2407.20964

@sth_fum

✅ مسئله قدیمی کوانتوم بالاخره حل شد

#اخبار_علمی_و_پژوهشی

پاسخ به یک سوال چند دهه‌ای در نظریه درهمتنیدگی کوانتومی سوالات بیشتری را در مورد این پدیده عجیب و غریب ایجاد می کند. فیزیکدانان فهرستی طولانی از مسائل باز که آنها را برای پیشبرد حوزه اطلاعات کوانتومی مهم می دانند، تهیه کرده‌اند. مسئله 5 می پرسد که آیا یک سیستم در سناریوی واقع گرایانه ای که در آن ...

📣 متن کامل را در Instant View ⚡️ (دکمه پایین صفحه) و یا در وب‌گاه انجمن فیزیک ایران بخوانید:
🚩http://www.psi.ir/news2_fa.asp?id=4102

⏪ وب‌گاه انجمن فیزیک ایران:
🌍 http://www.psi.ir

✅ به کانال خبرى انجمن فیزیک ايران بپيوندید:
👇👇🏽👇👇🏽👇👇🏽👇
http://t.me/psinews

جاذب لورنز یک جواب آشوبناک برای سیستم دینامیکی داده شده در معادلات بالا (با مقدارهای مشخصی برای پارامترهای β, ρ,σ) است. اگر ذره ای را فرض کنیم که مختصات آن توسط این معادلات تحول می‌یابد. مسیر آن (با شروع از نقطه آبی) به این شکل خواهد بود. این سیستم می تواند به عنوان یک مدل برای تغییردما در هوا بکار رود. یکی از مختصات نماینده نرخ همرفت و دوتای دیگر تغییر دما در دو جهت. بنابراین این جواب آشوبناک می تواند یک نمونه از «اثر پروانه ای» باشد. تغییرات کوچک در شرایط اولیه به نتایج بسیار متفاوتی منجر می شوند. این گونه سیستم ها با وجود کاملا موجبیتی بودن در بلند مدت غیرقابل پیش بینی هستند.
کد متمتیکا برای این شکل:

s = NDSolve[{x'[t] == -10 (x[t] - y[t]), 
    y'[t] == -x[t] z[t] + 28 x[t] - y[t], 
    z'[t] == x[t] y[t] - 8/3 z[t], x[0] == z[0] == 0, y[0] == 1}, {x, 
    y, z}, {t, 0, 400}, MaxSteps -> \[Infinity]];
Show[ParametricPlot3D[Evaluate[{x[t], y[t], z[t]} /. s], {t, 0, 400}, 
  PlotPoints -> 10000, PlotStyle -> Thickness[.0013], 
  ColorFunction -> (ColorData["SolarColors"][#4] &)], 
 Graphics3D[{Blue, Sphere[First[({x[0], y[0], z[0]} /. s)], .55]}], 
 Boxed -> False, Axes -> False]

کدهای جالب و ساده در سایر محیط های برنامه نویسی را در صفحه ویکیپدیا می توانید پیدا کنید:
https://en.wikipedia.org/wiki/Lorenz_system

شبیه‌سازی‌ها در کیهان‌شناسی و شاخه‌های دیگر علوم امکان مطالعه دقیق‌تر و بررسی سناریوها و مدل‌های مختلف را به ما می‌دهند. در کیهان‌شناسی، با استفاده از شبیه‌سازی‌ها، می‌توانیم تشکیل ساختارهای کیهانی و تحول کیهان را بسیار دقیق‌تر و با جزئیاتی بیشتر از آن‌چه که داده‌های رصدی فراهم می‌کنند مطالعه کنیم. می‌توانیم مدل‌های مختلف کیهان‌شناسی را در نظر بگیریم و برای آن‌ها شبیه‌سازی کنیم و با نتایج داده‌های رصدی مقایسه کنیم. شبیه‌سازی‌های کیهان‌شناسی هر روز دقیق‌تر و پیچیده‌تر و با جزئیات بیشتری در اختیار ما هستند. یکی از دقیق‌ترین شبیه‌سازی‌های بزرگ‌مقیاس کیهان‌شناسی، شبیه‌سازی illustrisTNG است. در ویدئویی که از لینک زیر قابل مشاهده است، می‌توانید بخشی از خروجی سه بعدی این شبیه‌سازی تشکیل ساختارهای کیهانی را تماشا کنید:
👇
https://www.youtube.com/watch?v=ECzyJ-vO8HQ&t=3s


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🇩🇪 PhD positions at the International Max Planck Research School for Astronomy & Astrophysics, Bonn Cologne 🇩🇪

The International Max Planck Research School (IMPRS) for Astronomy & Astrophysics is a joint structured Ph.D. program of the Max Planck Institute for Radioastronomy (MPIfR, Bonn) and the Universities of Bonn and Cologne. At one of the most vibrant astronomy centers in Europe, several PhD positions are available for talented students nearing the end of their Master's degree (or equivalent) in physics or astrophysics. The teaching language is English.

Program Details:

Appointments are for 3 years, starting at any time in 2025.
Starting annual gross salary: ~45,756 Euro; with attractive benefits.
The IMPRS for A&A has 60+ Ph.D. students from 22 countries.
Supervision by world-leading experts at the MPIfR and the Universities of Bonn and Cologne.
Research on a wide range of cutting-edge topics in observational and theoretical astrophysics.
Access to world-class observing facilities at a wide range of wavelengths.
Career development workshops, advanced lecture courses, soft skill seminars.
Funding for travel and research.

The application deadline is November 1st, 2024. For more information visit https://imprs.mpifr.de. To apply electronically, visit https://imprs.mpifr-bonn.mpg.de.

🇩🇪 Max Planck Research Group Leader, Hannover/Potsdam, Germany 🇩🇪

The Max Planck Society invites all scientists with a doctorate to apply for one of several positions as Max Planck Research Group Leader.

Successful candidates will be offered their own Max Planck Research Group at a participating Max Planck Institute of their own choice for an initial period of six years. As a Max Planck Research Group Leader, you will enjoy a world-class research environment at a Max Planck Institute with state-of-the-art infrastructure, administrative support, and the intellectual freedom to pursue an original research programme. The funding package of up to 2.7 Mio euros includes a German W2 position (equivalent to an assistant or untenured associate professorship), additional resources for the hiring of scientific staff and a budget to realize the project.
To submit your application online and for more details about the programme, please visit:
https://mprg.mpg.de

The deadline for applications is 14 October 2024.

For more information about the Max Planck Society and its institutes, please see:
https://www.mpg.de/en/

🇵🇱 Postdoc position, Wroclaw, Poland 🇵🇱

The group of Prof. A. Sedrakian at the Institute of Theoretical Physics, University of Wroclaw invites applications to fill one postdoc position. The successful candidate is expected to work in one of the following fields:

1) transport and weak processes in dense baryon matter at high densities and temperatures characteristic for neutron star mergers
2) transport and neutrino interactions within hybrid stars containing different phases of deconfined quark matter.
3) relativistic hydrodynamics and application to neutron stars.

The position is for two years, with a possible extension for a third year upon satisfactory performance.

Researchers in theoretical astro and nuclear physics or related areas are encouraged to apply. The candidates should have a PhD degree by the starting date of 01.01.2025 or the date of mutual agreement.

Applications should include
1) CV and list of publications,
2) research statement,
3) and arrange for three letters of recommendation to be sent by references to armen.sedrakian@uwr.edu.pl