[et_pb_section fb_built=”1″ fullwidth=”on” _builder_version=”4.14.8″ _module_preset=”default” background_image=”\/wp-content\/uploads\/2022\/04\/slider-corpo2.jpg” height=”114px” global_colors_info=”{}”][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.14.8″ _module_preset=”default” custom_margin=”||0px||false|false” custom_padding=”||0px||false|false” global_colors_info=”{}”][et_pb_row _builder_version=”4.14.8″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.14.8″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.14.8″ _dynamic_attributes=”content” _module_preset=”default” custom_margin=”0px||0px||false|false” custom_padding=”0px||0px||false|false” global_colors_info=”{}”]@ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoicG9zdF90aXRsZSIsInNldHRpbmdzIjp7ImJlZm9yZSI6IjxoMSBjbGFzcz1cImVudHJ5X3RpdGxlXCI+IiwiYWZ0ZXIiOiI8L2gxPiJ9fQ==@[\/et_pb_text][et_pb_text _builder_version=”4.14.8″ _dynamic_attributes=”content” _module_preset=”default” custom_margin=”0px|5px|0px||false|false” custom_padding=”0px||0px||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″ custom_css_main_element=”display: inline-block;”]@ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoiY3VzdG9tX21ldGFfZmVjaGFfZXZlbnRvIiwic2V0dGluZ3MiOnsiYmVmb3JlIjoiIiwiYWZ0ZXIiOiIiLCJlbmFibGVfaHRtbCI6Im9mZiJ9fQ==@[\/et_pb_text][et_pb_text _builder_version=”4.14.8″ _dynamic_attributes=”content” _module_preset=”default” custom_margin=”0px|5px|0px||false|false” custom_padding=”0px||0px||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″ custom_css_main_element=”display: inline-block;”]@ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoiY3VzdG9tX21ldGFfaG9yYV9ldmVudG8iLCJzZXR0aW5ncyI6eyJiZWZvcmUiOiIiLCJhZnRlciI6IiIsImVuYWJsZV9odG1sIjoib2ZmIn19@[\/et_pb_text][et_pb_text _builder_version=”4.14.8″ _dynamic_attributes=”content” _module_preset=”default” custom_margin=”0px||0px||false|false” custom_padding=”0px||0px||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″ module_class=”event-organizations”]@ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoiY3VzdG9tX21ldGFfb3JnYW5pemFjaW9uZXMiLCJzZXR0aW5ncyI6eyJiZWZvcmUiOiIiLCJhZnRlciI6IiIsImVuYWJsZV9odG1sIjoib2ZmIn19@[\/et_pb_text][et_pb_text _builder_version=”4.14.8″ _dynamic_attributes=”content” _module_preset=”default” custom_margin=”0px||0px||false|false” custom_padding=”0px||0px||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]@ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoiY3VzdG9tX21ldGFfbHVnYXJfZXZlbnRvIiwic2V0dGluZ3MiOnsiYmVmb3JlIjoiIiwiYWZ0ZXIiOiIiLCJlbmFibGVfaHRtbCI6Im9mZiJ9fQ==@[\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.14.8″ _module_preset=”default” custom_margin=”0px||||false|false” custom_padding=”0px||||false|false” top_divider_color=”RGBA(255,255,255,0)” top_divider_height=”0px” global_colors_info=”{}”][et_pb_row _builder_version=”4.14.8″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.14.8″ _module_preset=”default” global_colors_info=”{}”][et_pb_image src=”https:\/\/www.ieec.cat\/wp-content\/uploads\/2022\/12\/1556786525_1addd9111410461727570667dd2ca484_image_1349.jpg” alt=”Non-perturbative techniques in strongly coupled field theories” title_text=”Non-perturbative techniques in strongly coupled field theories” _builder_version=”4.14.8″ _module_preset=”default” width=”600px” module_alignment=”center” global_colors_info=”{}”][\/et_pb_image][et_pb_text _builder_version=”4.14.8″ _module_preset=”default” global_colors_info=”{}”]Non-perturbative techniques are needed to study strongly coupled systems. One powerful approach is the n-particle irreducible effective action. The method provides a systematic expansion for which the truncation occurs at the level of the action.<\/p>\n
The standard renormalisation procedure can be modified at the 2PI level by introducing multiple sets of counterterms, but counterterms cannot be used at higher orders. We have developed a method based on a renormalisation group approach which allows us to construct a renormalised theory at any order in the nPI approximation. Both the 2PI and 4PI theories can be renormalised using one bare coupling constant and one bare mass, which are introduced at the level of the lagrangian. We present results from a calculation using a scalar theory with quartic coupling in 4 dimensions, at the 4 loop level.[\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section]<\/p>\n","protected":false},"excerpt":{"rendered":"
Non-perturbative techniques are needed to study strongly coupled systems. One powerful approach is the n-particle irreducible effective action. The method provides a systematic expansion for which the truncation occurs at the level of the action. The standard renormalisation procedure can be modified at the 2PI level by introducing multiple sets of counterterms, but counterterms cannot […]<\/p>\n","protected":false},"author":0,"featured_media":6804,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"on","_et_pb_old_content":"","_et_gb_content_width":"2880","footnotes":""},"categories":[72,94],"tags":[],"class_list":["post-6808","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-events","category-talk"],"yoast_head":"\n